Wait for the expected target during a collapse

Actually wait for the collapsed item to complete. If complete is called
with other target, instead of simply returning and do nothing, wait again
until the proper target triggers the event (otherwise this leaves collapse
in a broken state).
fix #13340 by documenting @icon-font-path & @icon-font-name more
Merge pull request #13353 from twbs/fix-13340

Document @icon-font-path & @icon-font-name more
Merge pull request #13330 from Kronuz/patch-1

Wait for the expected target during a collapse