Prevent double email notifications on talk page edit

If a user is watching his/her own talk, an edit to the talk page
may trigger an echo notification and watchlist notification.  We
only want to send one of them

Depends on core patch: https://gerrit.wikimedia.org/r/#/c/114682/

Bug: 53569
Change-Id: Ib1bb71e047789d3a857f028aaa45384022bb35c7
Merge "Prevent double email notifications on talk page edit"