fix: run fixer tools in the repo root as cwd so they can use the working copy
This lets fixer tools do things like find configuration files, with the caveat
that they'll only see the version of that file in the working copy, regardless
of what revisions are being fixed.
Differential Revision: https://phab.mercurial-scm.org/D6440
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 https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.