[Fix rubocop#12761] Fix a false positive for Style/HashEachMethods

Fixes rubocop#12761.

This PR fixes a false positive for `Style/HashEachMethods`
when the key block argument of `Enumerable#each` method is unused after `chunk`.

changelog/fix_a_false_positive_for_style_hash_each_methods.md

@@ -0,0 +1 @@
+* [#12761](https://github.com/rubocop/rubocop/issues/12761): Fix a false positive for `Style/HashEachMethods` when the key block argument of `Enumerable#each` method is unused after `chunk`. ([@koic][])

lib/rubocop/cop/style/hash_each_methods.rb

@@ -40,7 +40,7 @@ class HashEachMethods < Base
 
         MSG = 'Use `%<prefer>s` instead of `%<current>s`.'
         UNUSED_BLOCK_ARG_MSG = "#{MSG.chop} and remove the unused `%<unused_code>s` block argument."
-        ARRAY_CONVERTER_METHODS = %i[assoc flatten rassoc sort sort_by to_a].freeze
+        ARRAY_CONVERTER_METHODS = %i[assoc chunk flatten rassoc sort sort_by to_a].freeze
 
         # @!method kv_each(node)
         def_node_matcher :kv_each, <<~PATTERN

spec/rubocop/cop/style/hash_each_methods_spec.rb

@@ -185,6 +185,12 @@
         RUBY
       end
 
+      it 'does not register an offense when the key block argument of `Enumerable#each` method is unused after `chunk`' do
+        expect_no_offenses(<<~RUBY)
+          foo.chunk { |i| i.do_something }.each { |unused_key, v| do_something(v) }
+        RUBY
+      end
+
       it 'does not register an offense when the key block argument of `Enumerable#each` method is unused after `flatten`' do
         expect_no_offenses(<<~RUBY)
           foo.flatten.each { |unused_key, v| do_something(v) }