phabricator: allow specifying reviewers on phabsend
Sometimes people want to specify reviewer explicitly for a stack. The
webpage only allows changing reviewer for one revision at a time. This patch
adds a `--reviewer` flag to make it easier to specify reviewers.
Test Plan:
On a test Phabricator instance, enable `differential.allow-self-accept`,
assign myself as a reviewer and make sure it works. Also try an invalid
username and make sure it raises.
Differential Revision: https://phab.mercurial-scm.org/D38
$ hg init
$ echo This is file a1 > a
$ hg add a
$ hg commit -m "commit #0"
$ ls
a
$ echo This is file b1 > b
$ hg add b
$ hg commit -m "commit #1"
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
B should disappear
$ ls
a