improve regrex for match(sidekiq) robustness

e.g.: the sidekiq in my Debian box is v2.11.1
Its time for 5.2.0.rc1
Fix typo in install docs, closes #3723
Typo fixes
Gitlab-shell should be 1.4.0 for GitLab 5.2
Update docs for 5.2
Typo fix closes gitlabhq/gitlabhq/3984
Fixed grammatical error.
Merge pull request #3988 from crazyscience/patch-3

Fixed grammatical error.
Merge pull request #3987 from bbodenmiller/patch-3

Typo fix in database.md closes 3984
Merge pull request #3983 from bbodenmiller/patch-1

Typo fixes in cleanup.md
Merge pull request #3972 from Razer6/master

Fix small typo in install docs, Closes #3723
changed Gitlab to GitLab
Merge pull request #3990 from bbodenmiller/patch-gitlab-cap

changed Gitlab to GitLab in user facing locations
Better remove project message
Version up to 5.2
Replace 5-1-stable with 5-2-stable in installation docs
Fix cancel button link on edit files page
Merge pull request #4018 from dolphin333/fix_cancel_button_link_on_edit_files_page

Fix cancel button link on edit files page
handle broken diffs gracefully