Change copy of talk page link in personal tools

Change copy of talk page link in personal tools

Adds message with key "mytalk-parenthetical", specifying the
text for "Talk" when it is wrapped in parentheses and
conjoined to the user page label.

Change is guarded by config variable "wgVectorCombineUserTalk",
set to false by default (which preserves the old behavior).

Per discussion on IRC and in
https://bugzilla.wikimedia.org/show_bug.cgi?id=41672

Change-Id: I822a73901c9b220983356e9e4a4ad5e7f8ebc7f1