revlog: add support for partial matching of wdir node id
The idea is simple. If the given node id prefix is 'ff...f', add +1 to the
number of matches (e.g. ambiguous if partial + maybewdir > 1).
This patch also fixes id() revset and shortest() template since _partialmatch()
can raise WdirUnsupported exception.
%include map-cmdline.default
changeset = '{cset}{branches}{bookmarks}{tags}{lphase}{parents}{user}{ldate}{summary}\n'
changeset_verbose = '{cset}{branches}{bookmarks}{tags}{lphase}{parents}{user}{ldate}{lfiles}{lfile_copies_switch}{description}\n'