Created by: hcgraf
In Mercurial, "bookmarks" is the concept which closely resembles "branches" in git. (real mercurial "branches" are part of a commits metadata, afaik there is nothing like that in git)
Many developers use bookmarks instead of named branches, so the display of the current branch is not very useful for them.
This PR checks if there is an active bookmark in the current repository ("active" means it would be moved with a commit).
If so, the bookmark name will be shown together with the branch name as branch,bookmark.
If there is no currently active bookmark, only branch (no trailing comma) will be shown.
Tested with bash & zsh.