[ruby/rdoc] Avoid potentially loading the same extension from different versions of the same gem
Avoids warnings like
/path/to/ruby/3.3.4/lib/ruby/gems/3.3.0/gems/rbs-3.4.0/lib/rdoc/discover.rb:10: warning: method redefined; discarding old scan /path/to/ruby/3.3.4/lib/ruby/gems/3.3.0/gems/rbs-3.5.1/lib/rdoc/discover.rb:10: warning: previous definition of scan was here
[ruby/rdoc] Avoid potentially loading the same extension from different versions of the same gem
Avoids warnings like
https://github.com/ruby/rdoc/commit/e47920d8f3