[v4] exclude_lines from pyproject.toml not respected

[jakkdl]

In python-trio/trio#2951 we're trying to update to codecov-action@v4, and among other things we noticed a drop in coverage that seems to be due to our exclude_lines setting in pyproject.toml not being respected.

https://github.com/CoolCat467/trio/blob/c806b2056d6c39ee3399eadccb757874ca593f9f/pyproject.toml#L261-L282
ignores, among other things, if TYPE_CHECKING.*: and raise NotImplementedError, but looking at a file such as https://app.codecov.io/gh/python-trio/trio/pull/2951/blob/src/trio/_socket.py we can see lines matching those are marked as misses.