Merge pull request #21167 from AaronLasseigne/use_each_key

replace each with each_key when only the key is needed

actionpack/lib/action_dispatch/routing/route_set.rb

@@ -271,7 +271,7 @@ def handle_positional_args(controller_options, inner_options, args, result, path
                 path_params -= controller_options.keys
                 path_params -= result.keys
               end
-              inner_options.each do |key, _|
+              inner_options.each_key do |key|
                 path_params.delete(key)
               end
 

activesupport/lib/active_support/multibyte/unicode.rb

@@ -338,7 +338,7 @@ def load
           end
 
           # Redefine the === method so we can write shorter rules for grapheme cluster breaks
-          @boundary.each do |k,_|
+          @boundary.each_key do |k|
             @boundary[k].instance_eval do
               def ===(other)
                 detect { |i| i === other } ? true : false