mediawiki.action.edit: Merge with mediawiki.action.edit.stash

mediawiki.action.edit: Merge with mediawiki.action.edit.stash

This module isn't used anywhere else. It was probably put into a
separate module due to the conditional loading. Though that can
be done client-side just as easily.

If we want to make it loaded conditionally, we could make the
module composition conditionally (which is straight-forward since
the condition doesn't vary on anything within the wiki).

* Follow-up 3a6c9d36: Remove 'jquery.getAttrs' from dependencies (unused).

Change-Id: Ic32da6f9b1c85eb106394b412fab9b22e0928323