Edit notices can now be translated.

Edit notices can now be translated.

Change editnotice from content language to user language. I see no
need to disable possible translations (for multilingual wikis). As
there is no default content, it'll always default to the editnotice
in the content language anyway. Slashes in page titles are converted
to hyphens, so there are no collisions.

Patch set 3, 4: Rebase against master

Patch set 5: wrap commit msg

Change-Id: I3d7ccec0bf407324821c3c853a60c27db5e5c519