tests: correct Windows output to account for putting repos in `repo` subdir These were missed in 55c6ebd11cb9, due to being conditionalized and not running in CI.

tests: use pattern matching to mask `ECONNREFUSED` messages The second and third one of these in `test-http-proxy.t` was failing on Windows. The others were found by grep and by failed tests when output was matched and an attempt was made to emit the mask pattern. The first clonebundles failure on Windows emitted: error fetching bundle: [WinError 10061] $ECONNREFUSED$ We should probably stringify that better to get rid of the "[WinError 10061]" part.

typing: add stub functions for `cext/charencoding` I'm not sure if it's better to have a separate file, and currently pytype doesn't really know how to handle these, so it's no help in figuring that out. Technically, these methods are part of the `mercurial.cext.parsers` module, so put them into the existing stub until there's a reason to split it out.

interfaces: introduce and use a protocol class for the `charencoding` module See f2832de2a46c for details when this was done for the `bdiff` module. This lets us dump the hack where the `pure` implementation was imported during the type checking phase to provide signatures for the module methods it provides. Now the protocol classes are starting to shine, because these methods are provided by `pure.charencoding` and `cext.parsers`, and references to `cffi.charencoding` and `cext.charencoding` are forwarded to them as appropriate by the `policy` module. But none of that matters, as long as the module returned provides the listed methods. The interface was copy/pasted from the `pure` module, but `jsonescapeu8fallback` is omitted because it is accessed from the `pure` module directly when the escaping fails in the primary module's `jsonescapeu8()`.

debugantivirusrunning: use bytes when opening a vfs file I noticed this when searching for "base85" to see if anything else in the previous commit needed to be annotated. This was added in 87047efbc6a6, after the mass byteification in 687b865b95ad.

interfaces: introduce and use a protocol class for the `base85` module See f2832de2a46c for details when this was done for the `bdiff` module. It looks like PEP-688 removed the special casing of `bytes` being a standin for any type of `ByteString`, and defines a `typing.Buffer` class (with a backport in `typing_extensions` for Python prior to 3.12). There's been a lot of churn in this area with pytype, but recent versions of pytype and PyCharm recognize this, and e.g. have `mercurial.node.hex()` defined as: from typing_extensions import Buffer def hex(data: Buffer, sep: str | bytes = ..., bytes_per_sep: int = ...) -> bytes This covers `bytes`, `bytearray`, and `memoryview` by default. Both of the C functions here use `y#` to parse the arguments, which means the arg is a byte-like object[2], so the args would appear to be better typed as `Buffer`. However, pytype has a bug that prevents using this from `typing_extensions`[3], and mypy complained `Unsupported left operand type for + ("memoryview")` in the pure module on line 37 (meaning it's only a subset of `Buffer`). So hold off on changing any of that for now. [1] https://peps.python.org/pep-0688/#no-special-meaning-for-bytes [2] https://docs.python.org/3/glossary.html#term-bytes-like-object [3] https://github.com/google/pytype/issues/1772