Internationalize menu accelerator for quit instruction bubble

The message always used to say "Press Alt+F followed by X to exit".  The "X"
comes from the menu option "Exit".  But the accelerator may be different in
non-English languages.  This CL internationalizes the accelerator.

BUG=243164
R=sky

Change-Id: I695979eef5ea15f1764b891611b2c513302c4c0e
Reviewed-on: https://chromium-review.googlesource.com/1194976
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587786}
7 files changed