zsh_completion: make use of `debuglabelcomplete` command
Use `debuglabelcomplete` command when populating labels list, instead of
calling `hg` three times: for branches, bookmarks and tags. Do not pass string
being completed to `hg debuglabelcomplete` (as `$words[$CURRENT]`), since it
breaks `_hg_revrange` completion (`--rev 2.5:2.5.<Tab>`) for no apparent
benefit.
Also complete `hg view` with labels, not just tags, and drop unused `_hg_tags`.
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing:
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.