Fix method redefinition warnings when pluralizations are reloaded

Fix: #735

Whenever pluralization rules are reloaded it causes a lot of warnings:

```
lib/rails_i18n/../../rails/pluralization/ar.rb:4: warning: method redefined; discarding old rule
lib/rails_i18n/../../rails/pluralization/ar.rb:4: warning: previous definition of rule was here
lib/rails_i18n/../../rails/pluralization/gd.rb:4: warning: method redefined; discarding old rule
lib/rails_i18n/../../rails/pluralization/gd.rb:4: warning: previous definition of rule was here
lib/rails_i18n/../../rails/pluralization/hsb.rb:4: warning: method redefined; discarding old rule
lib/rails_i18n/../../rails/pluralization/hsb.rb:4: warning: previous definition of rule was here
lib/rails_i18n/../../rails/pluralization/lt.rb:4: warning: method redefined; discarding old rule
lib/rails_i18n/../../rails/pluralization/lt.rb:4: warning: previous definition of rule was here
lib/rails_i18n/../../rails/pluralization/lv.rb:4: warning: method redefined; discarding old rule
lib/rails_i18n/../../rails/pluralization/lv.rb:4: warning: previous definition of rule was here
lib/rails_i18n/../../rails/pluralization/mk.rb:4: warning: method redefined; discarding old rule
lib/rails_i18n/../../rails/pluralization/mk.rb:4: warning: previous definition of rule was here
lib/rails_i18n/../../rails/pluralization/pl.rb:4: warning: method redefined; discarding old rule
lib/rails_i18n/../../rails/pluralization/pl.rb:4: warning: previous definition of rule was here
lib/rails_i18n/../../rails/pluralization/sl.rb:4: warning: method redefined; discarding old rule
lib/rails_i18n/../../rails/pluralization/sl.rb:4: warning: previous definition of rule was here
...
```

This is mostly harmless, but annoying for users who try to run with no warnings at all.

lib/rails_i18n/pluralization.rb

@@ -0,0 +1,143 @@
+module RailsI18n
+  module Pluralization
+    module Arabic
+      def self.rule
+        lambda do |n|
+          return :other unless n.is_a?(Numeric)
+
+          mod100 = n % 100
+
+          if n == 0
+            :zero
+          elsif n == 1
+            :one
+          elsif n == 2
+            :two
+          elsif (3..10).to_a.include?(mod100)
+            :few
+          elsif (11..99).to_a.include?(mod100)
+            :many
+          else
+            :other
+          end
+        end
+      end
+    end
+
+    module ScottishGaelic
+      def self.rule
+        lambda do |n|
+          return :other unless n.is_a?(Numeric)
+
+          floorn = n.floor
+
+          if floorn == 1 || floorn == 11
+            :one
+          elsif floorn == 2 || floorn == 12
+            :two
+          elsif (3..19).member?(floorn)
+            :few
+          else
+            :other
+          end
+        end
+      end
+    end
+
+    module UpperSorbian
+      def self.rule
+        lambda do |n|
+          return :other unless n.is_a?(Numeric)
+
+          mod100 = n % 100
+
+          case mod100
+          when 1 then :one
+          when 2 then :two
+          when 3, 4 then :few
+          else :other
+          end
+        end
+      end
+    end
+
+    module Lithuanian
+      def self.rule
+        lambda do |n|
+          return :other unless n.is_a?(Numeric)
+
+          mod10 = n % 10
+          mod100 = n % 100
+
+          if mod10 == 1 && !(11..19).to_a.include?(mod100)
+            :one
+          elsif (2..9).to_a.include?(mod10) && !(11..19).to_a.include?(mod100)
+            :few
+          else
+            :other
+          end
+        end
+      end
+    end
+
+    module Latvian
+      def self.rule
+        lambda do |n|
+          if n.is_a?(Numeric) && n % 10 == 1 && n % 100 != 11
+            :one
+          else
+            :other
+          end
+        end
+      end
+    end
+
+    module Macedonian
+      def self.rule
+        lambda do |n|
+          if n.is_a?(Numeric) && n % 10 == 1 && n != 11
+            :one
+          else
+            :other
+          end
+        end
+      end
+    end
+
+    module Polish
+      def self.rule
+        lambda do |n|
+          return :other unless n.is_a?(Numeric)
+
+          mod10 = n % 10
+          mod100 = n % 100
+
+          if n == 1
+            :one
+          elsif [2, 3, 4].include?(mod10) && ![12, 13, 14].include?(mod100)
+            :few
+          elsif [0, 1, 5, 6, 7, 8, 9].include?(mod10) || [12, 13, 14].include?(mod100)
+            :many
+          else
+            :other
+          end
+        end
+      end
+    end
+
+    module Slovenian
+      def self.rule
+        lambda do |n|
+          return :other unless n.is_a?(Numeric)
+
+          case n % 100
+          when 1 then :one
+          when 2 then :two
+          when 3, 4 then :few
+          else :other
+          end
+        end
+      end
+    end
+  end
+end

lib/rails_i18n/transliteration.rb

@@ -0,0 +1,191 @@
+# frozen_string_literal: true
+
+module RailsI18n
+  module Transliteration
+    module Ukrainian
+      class << self
+        def rule
+          lambda do |string|
+            next '' unless string
+
+            string.gsub(/./) do |char|
+              # Regexp.last_match is local to the thread and method scope
+              # of the method that did the pattern match.
+              @pre_match, @post_match = $`, $'
+
+              case char
+              when 'Ж'
+                lookahead_upcase 'ZH'
+              when 'Х'
+                lookahead_upcase 'KH'
+              when 'Ц'
+                lookahead_upcase 'TS'
+              when 'Ч'
+                lookahead_upcase 'CH'
+              when 'Ш'
+                lookahead_upcase 'SH'
+              when 'Щ'
+                lookahead_upcase 'SHCH'
+              when 'г'
+                behind =~ /[зЗ]/ ? 'gh' : 'h'
+              when 'Г'
+                behind =~ /[зЗ]/ ? lookahead_upcase('GH') : 'H'
+              when 'є'
+                letter?(behind) ? 'ie' : 'ye'
+              when 'Є'
+                letter?(behind) ? lookahead_upcase('IE') : lookahead_upcase('YE')
+              when 'ї'
+                letter?(behind) ? 'i' : 'yi'
+              when 'Ї'
+                letter?(behind) ? 'I' : lookahead_upcase('YI')
+              when 'й'
+                letter?(behind) ? 'i' : 'y'
+              when 'Й'
+                letter?(behind) ? 'I' : 'Y'
+              when 'ю'
+                letter?(behind) ? 'iu' : 'yu'
+              when 'Ю'
+                letter?(behind) ? lookahead_upcase('IU') : lookahead_upcase('YU')
+              when 'я'
+                letter?(behind) ? 'ia' : 'ya'
+              when 'Я'
+                letter?(behind) ? lookahead_upcase('IA') : lookahead_upcase('YA')
+              when "'"
+                # remove apostrophe inside a word
+                letter?(behind) && letter?(ahead) ? '' : "'"
+              else
+                straight_lookup[char] || char
+              end
+            end
+          end
+        end
+
+        private
+
+        def behind
+          @pre_match && @pre_match[-1]
+        end
+
+        def ahead
+          @post_match && @post_match[0]
+        end
+
+        def downcased?(symbol)
+          symbol =~ downcased_regexp
+        end
+
+        def downcased_regexp
+          @downcased_regexp ||= /[а-яґєії]/
+        end
+
+        # apostrophe can be inside a word
+        def letter?(symbol)
+          symbol =~ letter_regexp
+        end
+
+        def letter_regexp
+          @letter_regexp ||= /[а-яґєіїА-ЯҐЄІЇ'’]/
+        end
+
+        def lookahead_upcase(word)
+          downcased?(ahead) ? word.capitalize : word.upcase
+        end
+
+        def straight_lookup
+          @straight_lookup ||= {
+            'а'=>'a','б'=>'b','в'=>'v','ґ'=>'g','д'=>'d','е'=>'e','ж'=>'zh',
+            'з'=>'z','и'=>'y','і'=>'i','к'=>'k','л'=>'l','м'=>'m','н'=>'n','о'=>'o',
+            'п'=>'p','р'=>'r','с'=>'s','т'=>'t','у'=>'u','ф'=>'f','х'=>'kh','ц'=>'ts',
+            'ч'=>'ch','ш'=>'sh','щ'=>'shch','ь'=>'','’'=>'',
+            'А'=>'A','Б'=>'B','В'=>'V','Ґ'=>'G','Д'=>'D','Е'=>'E',
+            'З'=>'Z','И'=>'Y','І'=>'I','К'=>'K','Л'=>'L','М'=>'M','Н'=>'N','О'=>'O',
+            'П'=>'P','Р'=>'R','С'=>'S','Т'=>'T','У'=>'U','Ф'=>'F','Ь'=>''
+          }
+        end
+      end
+    end
+
+    # (c) Yaroslav Markin, Julian "julik" Tarkhanov and Co
+    # https://github.com/yaroslav/russian/blob/master/lib/russian/transliteration.rb
+    module Russian
+      class << self
+        def rule
+          lambda do |string|
+            next '' unless string
+
+            chars = string.scan(%r{#{multi_keys.join '|'}|\w|.})
+
+            result = +""
+
+            chars.each_with_index do |char, index|
+              if upper.has_key?(char) && lower.has_key?(chars[index+1])
+                # combined case
+                result << upper[char].downcase.capitalize
+              elsif upper.has_key?(char)
+                result << upper[char]
+              elsif lower.has_key?(char)
+                result << lower[char]
+              else
+                result << char
+              end
+            end
+
+            result
+          end
+        end
+
+        private
+
+        # use instance variables instead of constants to prevent warnings
+        # on re-evaling after I18n.reload!
+
+        def upper
+          @upper ||= begin
+            upper_single = {
+              "Ґ"=>"G","Ё"=>"YO","Є"=>"E","Ї"=>"YI","І"=>"I",
+              "А"=>"A","Б"=>"B","В"=>"V","Г"=>"G",
+              "Д"=>"D","Е"=>"E","Ж"=>"ZH","З"=>"Z","И"=>"I",
+              "Й"=>"Y","К"=>"K","Л"=>"L","М"=>"M","Н"=>"N",
+              "О"=>"O","П"=>"P","Р"=>"R","С"=>"S","Т"=>"T",
+              "У"=>"U","Ф"=>"F","Х"=>"H","Ц"=>"TS","Ч"=>"CH",
+              "Ш"=>"SH","Щ"=>"SCH","Ъ"=>"'","Ы"=>"Y","Ь"=>"",
+              "Э"=>"E","Ю"=>"YU","Я"=>"YA",
+            }
+
+            (upper_single.merge(upper_multi)).freeze
+          end
+        end
+
+        def lower
+          @lower ||= begin
+            lower_single = {
+              "і"=>"i","ґ"=>"g","ё"=>"yo","№"=>"#","є"=>"e",
+              "ї"=>"yi","а"=>"a","б"=>"b",
+              "в"=>"v","г"=>"g","д"=>"d","е"=>"e","ж"=>"zh",
+              "з"=>"z","и"=>"i","й"=>"y","к"=>"k","л"=>"l",
+              "м"=>"m","н"=>"n","о"=>"o","п"=>"p","р"=>"r",
+              "с"=>"s","т"=>"t","у"=>"u","ф"=>"f","х"=>"h",
+              "ц"=>"ts","ч"=>"ch","ш"=>"sh","щ"=>"sch","ъ"=>"'",
+              "ы"=>"y","ь"=>"","э"=>"e","ю"=>"yu","я"=>"ya",
+            }
+
+            (lower_single.merge(lower_multi)).freeze
+          end
+        end
+
+        def upper_multi
+          @upper_multi ||= { "ЬЕ"=>"IE", "ЬЁ"=>"IE" }
+        end
+
+        def lower_multi
+          @lower_multi ||= { "ье"=>"ie", "ьё"=>"ie" }
+        end
+
+        def multi_keys
+          @multi_keys ||= (lower_multi.merge(upper_multi)).keys.sort_by {|s| s.length}.reverse.freeze
+        end
+      end
+    end
+  end
+end
+

rails/pluralization/ar.rb

@@ -1,30 +1,4 @@
-module RailsI18n
-  module Pluralization
-    module Arabic
-      def self.rule
-        lambda do |n|
-          return :other unless n.is_a?(Numeric)
-
-          mod100 = n % 100
-
-          if n == 0
-            :zero
-          elsif n == 1
-            :one
-          elsif n == 2
-            :two
-          elsif (3..10).to_a.include?(mod100)
-            :few
-          elsif (11..99).to_a.include?(mod100)
-            :many
-          else
-            :other
-          end
-        end
-      end
-    end
-  end
-end
+require 'rails_i18n/pluralization'
 
 { :ar => {
     :'i18n' => {

rails/pluralization/gd.rb

@@ -1,26 +1,4 @@
-module RailsI18n
-  module Pluralization
-    module ScottishGaelic
-      def self.rule
-        lambda do |n|
-          return :other unless n.is_a?(Numeric)
-
-          floorn = n.floor
-
-          if floorn == 1 || floorn == 11
-            :one
-          elsif floorn == 2 || floorn == 12
-            :two
-          elsif (3..19).member?(floorn)
-            :few
-          else
-            :other
-          end
-        end
-      end
-    end
-  end
-end
+require 'rails_i18n/pluralization'
 
 { :gd => {
     :'i18n' => {