Easily (un)mark merge request as WIP using link

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/3768 and https://gitlab.com/gitlab-org/gitlab-ce/issues/3516

Link to add WIP prefix (underline is visible because of hover)

Link to remove WIP prefix

System note after WIP is added

Widget with link to remove WIP

Flash after WIP is removed

System note after WIP is removed

Widget when current user cannot remove the WIP prefix

cc @creamzy

@DouweM @rspeicher great :thumbs_up_reverse: every place is thought through

Pinging @jschatz1 for CS review -- I think we need to off the same events due to our dumb dispatcher, don't we?

Reassigned to @DouweM

@rspeicher If that's your only question... Use event delegation and chain them. Something like:

  $(document)
    .off 'click', '.gutter-toggle'
    .on 'click', '.gutter-toggle', (e) ->

But yes we do.

@DouweM Will this be ready for 8.6? :)

Added ~13921 label

Added frontend label

@rymai I hope to have time today.

Added 1012 commits:

• d4b49587...18fc7c66 - 1010 commits from branch master
• 0b942541 - Improve the "easy WIP & un-WIP from link" feature
• cafa408b - Merge remote-tracking branch 'origin/master' into remove-wip

Added 1 commit:

• 4ce29395 - Remove CHANGELOG item that was added during merge resolution

@DouweM I have pushed improvements, I hope you don't mind.

Pinging @jschatz1 for CS review -- I think we need to off the same events due to our dumb dispatcher, don't we?

I haven't taken this in account, though. Not sure this is relevant here.

Anyways, I let @DouweM @rspeicher and @jschatz1 review.

@rymai I'like take a look as soon as I get a chance.

@rymai LGTM.

@jschatz1 I'll assign to you

Reassigned to @jschatz1

Added ~149423 label

@rymai Quite nice! LGTM. Merging.

mentioned in commit 3f22a92f

Status changed to merged

@jschatz1 @DouweM Awesome, thanks!

Picked into 8-6-stable, will go into 8.6.0-rc5.

Removed ~149423 label

mentioned in merge request gitlab-com/www-gitlab-com!1633 (merged)

mentioned in commit 42c43041