One of the existing problems with using phabricator for us is that there is no
way to specify that the revision/patch/differential is intended for stable
branch.
This patch adds a new flag --branch to hg phabsend command. If the
--branch is passed, hg phabsend will add a comment to the related
differential saying that The review is intended for a <branch-name> branch.
I looked into other API's which we can use or other properties which can be used
to put the branch info and didn't found anything quite useful.
Future improvement can be checking the branch of the patch and commenting that
branch name.
I am not sure how to add tests for this. I tested this patch while sending this
patch.