git-hgext: adjust to the lack of `changelog.heads` method We don't have a `heads` method returning nodeid, but this is very easy to get the same result. This was flagged by pytype. We can note that the fact this code did not break is probably a good sign that it is dead code. However this is a question outside of the scop of this series.

remotefilelog: drop dead code As pytype flagged bug in this method it highlighted that this methode being never called anywhere.

pytype: use the right signature for the `__delitem__` It is not because it is NotImplemented that it should use a bad signature. Fix it to please pytype.

pytype: use the right signature for the `__setitem__` It is not because it is NotImplemented that it should use a bad signature. Fix it to please pytype.

sparse: use with statement for wlock This will avoid pytype complaining about the try/except range.

remotefilelog: adjust the signature of basepack.createindex pytype point that the subclass signature have been updated.