Fix an incorrect autocorrect for Style/RedundantDoubleSplatHashBraces

This PR fixes the following incorrect autocorrect for `Style/RedundantDoubleSplatHashBraces`
when using double splat hash braces with `merge` method call twice.

```console
$ bundle exec rspec  spec/rubocop/cop/style/redundant_double_splat_hash_braces_spec.rb:82
Run options: include {:locations=>{"./spec/rubocop/cop/style/redundant_double_splat_hash_braces_spec.rb"=>[82]}}
(snip)

Failures:

  1) RuboCop::Cop::Style::RedundantDoubleSplatHashBraces registers an offense
     when using double splat hash braces with `merge` method call twice
     Failure/Error: expect(new_source).to eq(correction)

       expected: "do_something(foo: bar, **options)\ndo_something(baz: qux, **options)\n"
            got: "do_something(foo: bar, **options)\ndo_something(baz: qux.merge(options))\n"

       (compared using ==)

       Diff:
       @@ -1,3 +1,3 @@
        do_something(foo: bar, **options)
       -do_something(baz: qux, **options)
       +do_something(baz: qux.merge(options))

     # ./lib/rubocop/rspec/expect_offense.rb:164:in `expect_correction'
     # ./spec/rubocop/cop/style/redundant_double_splat_hash_braces_spec.rb:90:in `block (2 levels) in <top (required)>'

Finished in 0.15475 seconds (files took 1.24 seconds to load)
1 example, 1 failure
```

changelog/fix_incorrect_autocorrect_for_style_redundant_double_splat_hash_braces.md

@@ -0,0 +1 @@
+* [#12262](https://github.com/rubocop/rubocop/pull/12262): Fix an incorrect autocorrect for `Style/RedundantDoubleSplatHashBraces` when using double splat hash braces with `merge` method call twice. ([@koic][])

lib/rubocop/cop/style/redundant_double_splat_hash_braces.rb

@@ -84,7 +84,7 @@ def range_of_merge_methods(merge_methods)
         end
 
         def extract_send_methods(kwsplat)
-          @extract_send_methods ||= kwsplat.each_descendant(:send, :csend)
+          kwsplat.each_descendant(:send, :csend)
         end
 
         def convert_to_new_arguments(node)

spec/rubocop/cop/style/redundant_double_splat_hash_braces_spec.rb

@@ -79,6 +79,20 @@
     RUBY
   end
 
+  it 'registers an offense when using double splat hash braces with `merge` method call twice' do
+    expect_offense(<<~RUBY)
+      do_something(**{ foo: bar }.merge(options))
+                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Remove the redundant double splat and braces, use keyword arguments directly.
+      do_something(**{ baz: qux }.merge(options))
+                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Remove the redundant double splat and braces, use keyword arguments directly.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      do_something(foo: bar, **options)
+      do_something(baz: qux, **options)
+    RUBY
+  end
+
   it 'registers an offense when using double splat hash braces with `merge` multiple arguments method call' do
     expect_offense(<<~RUBY)
       do_something(**{foo: bar, baz: qux}.merge(options1, options2))