typing: add a handful more annotations to `mercurial/vfs.py` These came out of refactoring into a protocol class, but they can stand on their own. The `audit` callback is kinda screwy because the internal lambda and the callable for `pathutil.pathauditor` have different args and a different return type. It's conditionalized where it is called, and can be cleaned up later if desired.

typing: make `vfs.isfileorlink_checkdir()` path arg required The only caller to this is `merge._checkunknownfile()`, which supplies a value. That's good, because `util.localpath()` immediately uses the value to call a method on it on Windows. The posix implementation returns the value unaltered, but then `pathutil.finddirs_rev_noroot()` would have exploded.

typing: manually add type annotations to `mercurial/vfs.py` This isn't everything, but hopefully it's close enough to hack on a protocol class.

typing: correct pytype mistakes in `mercurial/vfs.py` With the previous changes in this series (prior to merging the *.pyi file), this wasn't too bad- the only definitively wrong things were the `data` argument to `writelines()`, and the return type on `backgroundclosing()` (both of these errors were dropped in the previous commit; for some reason pytype doesn't like `contextlib._GeneratorContextManager`, even though that's what it determined it is): File "/mnt/c/Users/Matt/hg/mercurial/vfs.py", line 411, in abstractvfs: Bad return type 'contextlib._GeneratorContextManager' for generator function abstractvfs.backgroundclosing [bad-yield-annotation] Expected Generator, Iterable or Iterator PyCharm thinks this is `Generator[backgroundfilecloser], Any, None]`, which can be reduced to `Iterator[backgroundfilecloser]`, but pytype flagged the line that calls `yield` without an argument unless it's also `Optional`. PyCharm is happy either way. For some reason, `Iterable` didn't work for pytype: File "/mnt/c/Users/Matt/hg/mercurial/vfs.py", line 390, in abstractvfs: Function contextlib.contextmanager was called with the wrong arguments [wrong-arg-types] Expected: (func: Callable[[Any], Iterator]) Actually passed: (func: Callable[[Any, Any, Any], Iterable[Optional[Any]]]) Attributes of protocol Iterator[_T_co] are not implemented on Iterable[Optional[Any]]: __next__

typing: run `merge-pyi` on `mercurial/vfs.py` The *.pyi file was generated with pytype 2023.11.21. There were a few things here that were wrong (e.g. `writelines()` takes an `Iterable[bytes]`, not `bytes`, or inexplicable errors like importing several of the vfs classes from this very module), and those changes have been dropped manually here.

typing: add type annotations to `mercurial.util.makelock()` This bubbles up into the `vfs` classes, so get this out of the way.

util: avoid a leaked file descriptor in `util.makelock()` exceptional case

typing: add type annotations to the `mercurial.util.filestat` class It's referenced in the `vfs` classes, so get this out of the way to help there. The `TypeVar` definition and its usage was copied from the existing `util.pyi` file.

vfs: do minor copyediting on comments and doc strings These were flagged by PyCharm, so clear them from the gutter.

vfs: simplify the `abstractvfs.rename()` implementation PyCharm was yapping about `util.rename()` not returning anything, because it is typed to return `None`, but the value was captured and returned after calling `_avoidambig()`. Instead, drop all of that, unconditionally rename, and then call `_avoidambig()` if appropriate. While we're here, convert the ersatz ternary operator into a modern one to help pytype. When a variable is initialized the old way, pytype tends to assign the type of the LHS of the `and`. In this case, that's a bool, and it will get confused that bool doesn't have a `stat` attribute once this method gets more type annotations. (Currently it thinks the `checkambig` arg is `Any`, so it doesn't care.)