links in help index page links to error page when access it with url `https://gitlab.example.com/help/`

Summary

When access help index page with url https://gitlab.example.com/help/ which have an extra slash, links are failed to direct to correct page

Steps to reproduce

access help index page with url https://gitlab.example.com/help/

Expected behavior

links should direct to correct page

Actual behavior

links directed to a 404 error page

Possible fixes

line 11 at app/controllers/help_controller.rb

    @help_index.gsub!(/(\]\()(?!help\/)([^\)\(]+)(\))/, '\1help/\2\3')

should be

   @help_index.gsub!(/(\]\()(?!help\/)([^\)\(]+)(\))/, '\1/help/\2\3')