dirstate: add explicit methods for querying directories (API)
The set-like object returned by dirstate.dirs may be difficult for other
implementations of the dirstate to provide, and is unnecessary as it is
only ever used for __contains__. Instead, provide an explicit method for
testing for a directory.
.. api::
dirstate no longer provides a `dirs()` method. To test for the existence of
a directory in the dirstate, use `dirstate.hasdir(dirname)`.
Differential Revision: https://phab.mercurial-scm.org/D1345
Our full contribution guidelines are in our wiki, please see:
https://www.mercurial-scm.org/wiki/ContributingChanges
If you just want a checklist to follow, you can go straight to
https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist
If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).