discovery: fix docstring of `outgoing` class
Also, introduce a more correct name `ancestorsof` for what was named
`missingheads` before. For now, we just forward `ancestorsof` to `missingheads`
until all users are changed.
There were some mistakes in the old docstring / name:
* `missingheads` (new name: `ancestorsof`) contains the revs whose ancestors
are included in the outgoing operation. It may contain non-head revs and revs
which are already on the remote, so the name "missingheads" is wrong in two
ways.
* `missing` contains only ancestors of `missingheads`, so not *all nodes*
present in local but not in remote.
* `common` might not contain all common revs, e.g. not some that are not an
ancestor of `missingheads`.
It seems like the misleading name have fostered an actual bug (
issue6372),
where `outgoing.missingheads` was used assuming that it contains the heads of
the missing changesets.
# Rust builds with a modern MSVC and uses a newer CRT.
# Python 2.7 has a shared library dependency on an older CRT (msvcr90.dll).
# We statically link the modern CRT to avoid multiple msvcr*.dll libraries
# being loaded and Python possibly picking up symbols from the newer runtime
# (which would be loaded first).
[target.'cfg(target_os = "windows")']
rustflags = ["-Ctarget-feature=+crt-static"]