Remove duplicate sigil docs now that guides are included

lib/elixir/lib/macro.ex

@@ -61,75 +61,6 @@ defmodule Macro do
   > The functions in this module do not evaluate code. In fact,
   > evaluating code from macros is often an anti-pattern. For code
   > evaluation, see the `Code` module.
-
-  ## Custom Sigils
-
-  Macros are also commonly used to implement custom sigils.
-
-  Sigils start with `~` and are followed by one lowercase letter or by one
-  or more uppercase letters, and then a separator
-  (see the [Syntax Reference](syntax-reference.md)). One example is
-  `~D[2020-10-13]` to define a date.
-
-  To create a custom sigil, define a macro with the name `sigil_{identifier}`
-  that takes two arguments. The first argument will be the string, the second
-  will be a charlist containing any modifiers. If the sigil is lower case
-  (such as `sigil_x`) then the string argument will allow interpolation.
-  If the sigil is one or more upper case letters (such as `sigil_X` and
-  `sigil_EXAMPLE`) then the string will not be interpolated.
-
-  Valid modifiers are ASCII letters and digits. Any other character will
-  cause a syntax error.
-
-  Single-letter sigils are typically reserved to the language. Multi-letter
-  sigils are uppercased and extensively used by the community to embed
-  alternative markups and data-types within Elixir source code.
-
-  The module containing the custom sigil must be imported before the sigil
-  syntax can be used.
-
-  ### Examples
-
-  As an example, let's define a sigil `~x` and sigil `~X` which
-  return its contents as a string. However, if the `r` modifier
-  is given, it reverses the string instead:
-
-      defmodule MySigils do
-        defmacro sigil_x(term, [?r]) do
-          quote do
-            unquote(term) |> String.reverse()
-          end
-        end
-
-        defmacro sigil_x(term, _modifiers) do
-          term
-        end
-
-        defmacro sigil_X(term, [?r]) do
-          quote do
-            unquote(term) |> String.reverse()
-          end
-        end
-
-        defmacro sigil_X(term, _modifiers) do
-          term
-        end
-      end
-
-      import MySigils
-
-      ~x(with #{"inter" <> "polation"})
-      #=> "with interpolation"
-
-      ~x(with #{"inter" <> "polation"})r
-      #=> "noitalopretni htiw"
-
-      ~X(without #{"interpolation"})
-      #=> "without \#{"interpolation"}"
-
-      ~X(without #{"interpolation"})r
-      #=> "}\"noitalopretni\"{# tuohtiw"
-
   """
 
   alias Code.Identifier

lib/elixir/pages/getting-started/sigils.md

@@ -237,4 +237,4 @@ iex> ~i(42)n
 
 Custom sigils may be either a single lowercase character or several uppercase characters.
 
-Sigils can also be used to do compile-time work with the help of macros. For example, regular expressions in Elixir are compiled into an efficient representation during compilation of the source code, therefore skipping this step at runtime. If you're interested in the subject, we recommend you learn more about macros and check out how sigils are implemented in the `Kernel` module (where the `sigil_*` functions are defined).
+Sigils can also be used to do compile-time work with the help of macros. For example, regular expressions in Elixir are compiled into an efficient representation during compilation of the source code, therefore skipping this step at runtime. If you're interested in the subject, you can learn more about macros and check out how sigils are implemented in the `Kernel` module (where the `sigil_*` functions are defined).