When bumping sphinx, remove FrameType workaround in docs/source/conf.py

[jakkdl]

sphinx-doc/sphinx#11802
sphinx-doc/sphinx#11861
being fixed should make

trio/docs/source/conf.py

Lines 200 to 203 in d1cc062

	# `types.FrameType.__module__` is "builtins", so sphinx looks for
	# builtins.FrameType.
	# See https://github.com/sphinx-doc/sphinx/issues/11802
	add_mapping("class", "types", "FrameType")

redundant. Though I had some issues with getting TracebackType working with their workaround previously:

trio/src/trio/testing/_raises_group.py

Lines 22 to 24 in d1cc062

	# sphinx will *only* work if we use types.TracebackType, and import
	# *inside* TYPE_CHECKING. No other combination works.....
	import types

that'll probably be the case with FrameType as well - and if so we should probably investigate and open an issue in sphinx about it.

[A5rocks]

This doesn't seem to work when updating Sphinx to 7.4.7 (I tried several combinations of from types import FrameType and moving things out of if TYPE_CHECKING but nothing changed).

[jakkdl]

I spent a while digging around in sphinx, and it appears I was wrong about the cause being types.FrameType.__module__ == 'builtins'. It's the same problem as with math.inf, where they're defined in the py:data section in the objects.inv file, rather than in py:class.

The open issues for this seem to be sphinx-doc/sphinx#10974 / sphinx-doc/sphinx#10785

[jakkdl]

pushed a commit to #3070 that fixes the comment, so we can probably close this. Don't think we need a dedicated tracking issue for it