When authors add inlines to their own revisions/commits, mark them as "Done" by default

Summary:
Ref T13195. Fixes T8573. When you're adding inlines to your own stuff, mark them "Done" by default. You can unmark them as "Done" if you're legitimately leaving TODOs for yourself, although I think this is unusual.

(If this turns out to be less unusual than I think, we could consider an alternate rule: mark replies by the author as "Done" by default.)

Test Plan: Added some inlines as an author and a non-author. Saw my author inlines marked as "Done" by default. Submitted them; unmarked and submittted them.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13195, T8573

Differential Revision: https://secure.phabricator.com/D19635