Fix false negatives for Style/RedundantRegexpArgument

This PR fixes false negatives for `Style/RedundantRegexpArgument`
when using safe navigation operator.

changelog/fix_false_negatives_for_style_redundant_regexp_argument.md

@@ -0,0 +1 @@
+* [#12010](https://github.com/rubocop/rubocop/pull/12010): Fix false negatives for `Style/RedundantRegexpArgument` when using safe navigation operator. ([@koic][])

lib/rubocop/cop/style/redundant_regexp_argument.rb

@@ -57,6 +57,7 @@ def on_send(node)
             corrector.replace(regexp_node, prefer)
           end
         end
+        alias on_csend on_send
 
         private
 

spec/rubocop/cop/style/redundant_regexp_argument_spec.rb

@@ -12,6 +12,17 @@
         'foo'.#{method}("f")
       RUBY
     end
+
+    it "registers an offense and corrects when the method with safe navigation operator is `#{method}`" do
+      expect_offense(<<~RUBY, method: method)
+        'foo'&.#{method}(/f/)
+               _{method} ^^^ Use string `"f"` as argument instead of regexp `/f/`.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        'foo'&.#{method}("f")
+      RUBY
+    end
   end
 
   it 'registers an offense and corrects when using double quote and single quote characters' do