Add troubleshooting note on gitlab-runner symlink removal
What does this MR do?
This MR updates the Runner troubleshooting to let people know to use /usr/bin/gitlab-runner once the symlink pointing /usr/lib/gitlab-runner to /usr/bin/gitlab-runner is removed.
Why was this MR needed?
This MR is needed as a part of the GitLab 14.0 Support Readiness effort.
What's the best way to test this MR?
The best way to test this MR is to confirm that the provided Markdown renders properly.
What are the relevant issue numbers?
gitlab-com/support/support-team-meta#3423 (closed)