gh-128152: Argument Clinic: don't parse CPP directives inside C comments

[erlend-aasland]

Resolves#128152

[picnixz]

I'm not an expert in AC but this looks good. At least, I can now use empty lines in python input. By the way, I think I've just understood that CPP stands for Clinic Pre-Processor/Processing and not for C++....

[erlend-aasland]

I can now use empty lines in python input

Yes, # prefixed lines are now correctly passed on as Python code. For clinic input blocks, they are correctly ignored as "Clinic comments":

cpython/Tools/clinic/libclinic/dsl_parser.py

Lines 493 to 496 in f157485

	defvalid_line(self, line: str) ->bool:
	# ignore comment-only lines
	ifline.lstrip().startswith('#'):
	returnFalse

[erlend-aasland]

Thanks for the quick review! I'll land this tomorrow.

[bedevere-app]

GH-128478 is a backport of this pull request to the 3.13 branch.