Fix a false negative for Layout/LeadingCommentSpace

This PR fixes a false negative for `Layout/LeadingCommentSpace`
when using `#+` or `#-` as they are not RDoc comments.

They are followed by `+` or `-` twice, such as `#++` and `#--`.

Author: koic

changelog/fix_a_false_negative_for_layout_leading_comment_space.md

@@ -0,0 +1 @@
+* [#12136](https://github.com/rubocop/rubocop/pull/12136): Fix a false negative for `Layout/LeadingCommentSpace` when using `#+` or `#-` as they are not RDoc comments. ([@koic][])

lib/rubocop/cop/layout/leading_comment_space.rb

@@ -57,7 +57,7 @@ class LeadingCommentSpace < Base
 
         def on_new_investigation
           processed_source.comments.each do |comment|
-            next unless /\A#+[^#\s=+-]/.match?(comment.text)
+            next unless /\A(?!#\+\+|#--)(#+[^#\s=])/.match?(comment.text)
             next if comment.loc.line == 1 && allowed_on_first_line?(comment)
             next if doxygen_comment_style?(comment)
             next if gemfile_ruby_comment?(comment)

spec/rubocop/cop/layout/leading_comment_space_spec.rb

@@ -143,6 +143,20 @@
       RUBY
     end
 
+    it 'registers an offense when using `#+` or `#-` as they are not RDoc comments' do
+      expect_offense(<<~RUBY)
+        #+
+        ^^ Missing space after `#`.
+        #-
+        ^^ Missing space after `#`.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        # +
+        # -
+      RUBY
+    end
+
     it 'registers an offense when starting `:`' do
       expect_offense(<<~RUBY)
         #:nodoc: