Ignore closed branch heads by default in Mercurial
Summary:
Fixes T6160. Ref T7100.
- When resolving ambiguous branch references, ignore closed heads unless there are no other options.
- Hide closed heads by default on the main page.
- Show branch open/closed state in Mercurial.
Test Plan: Browsed a previously-ambiguous Mercurial repository because of multiple branch heads, no longer ambiguous.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T6160, T7100
Differential Revision: https://secure.phabricator.com/D12552