docs(*): ensure naming is correct for Angular(JS) versions

This was originally done on the master branch in
commit 03043839d5a540b02208001fe12e812dfde00a8e,
but never back-ported to 1.6.x.

That wasn't a big deal because docs.angularjs.org
served the master snapshot docs. However, now we
serve the 1.6.x snapshot docs, and it looks strange
that the official docs have the wrong branding :).