typing: add type hints to bdiff implementations Not super important code, but this was an exercise in using `merge-pyi` to fold type stubs back into the code on something small. The cext stubs don't seem to be getting used (at least the only thing in `.pytype/pyi/mercurial/cext` after a run generating the stubs is `__init__.pyi`), so maybe this will help some.

cffi: adjust the list returned by bdiff.blocks to never have a None entry This was flagged by pytype after merging the corresponding bdiff.pyi in cext: File ".../mercurial/cffi/bdiff.py", line 44, in blocks: bad return type [bad-return-type] Expected: List[Tuple[int, int, int, int]] Actually returned: List[None] AFAICT, all callers immediately unpack the tuple into 4 variables, so a `None` entry would simply crash if they aren't all overwritten. As long a `count` and the link list are consistent, this shouldn't be a problem. This placates both pytype and PyCharm (which complained about the `i` in `rl[i]` having the wrong type with the old code).

typing: fix a syntax error in mercurial/cext/bdiff.pyi I noticed because `merge-pyi` on the non-cext implementations with this file as input skipped the return type for this. `pytype-single --parse-pyi` confirmed it was a problem.

hg-core: relax dependencies pinning Being this rigid makes packagers' job more difficult since they might not carry the exact version. This hard pinning was introduced in eb02decdf but wasn't strictly necessary to achieve its compatibility goal.

tests: make running ls in a no longer existing directory more portable On Linux, ls -A simply returns nothing and the exit code is 0. On NetBSD, ls -A complains that . doesn't exist and the exit code is 1. Sadly, it's not possible to do something like "[1] (?)", so " || true" is the best I could come up with.

tests: move some lines inside #if windows-#else block test-removeemptydirs.t This is done to make it's clear that windows is not affected by this test case, IOW windows and non-windows platforms are now tested separately, because their results are very different.

tests: use ls -A instead of ls -1 in test-removeemptydirs.t In case the tests are run as root, ls assumes -A by default on some systems (e.g. NetBSD). Tests probably shouldn't be run as root, but let's use -A just in case, for convenience.

release: add the "6.3" to the 6.3 release The release was tagged "6.3.0" while the custom have been to omit the third ".0" for initial release for the history of the project. For consistency, we add the customary version of the tag to the 6.3 release.