Merge branch 'commit-diff-discussion-in-mr-context-fix-links' into 'master'

fix the commit diff discussion sending the wrong url

See merge request gitlab-org/gitlab-ce!15988

(cherry picked from commit f7a9ced2)

c77083a4 fix the commit diff discussion sending the wrong url
a794b161 rework the merge_request_version_params to use Object#tap