Stubtest: Link directly to line

[Avasam]

This format allows editors and terminals that support linking to specific lines in files to go directly to the right line.

Before:

After:

[AlexWaygood]

Looks like you'll need to update some bits of teststubtest.py, e.g.

mypy/mypy/test/teststubtest.py

Lines 1518 to 1525 in 77f8725

	expected = (
	f'error: {TEST_MODULE_NAME}.bad is inconsistent, stub argument "number" differs '
	'from runtime argument "num"\n'
	f"Stub: at line 1 in file {TEST_MODULE_NAME}.pyi\n"
	"def (number: builtins.int, text: builtins.str)\n"
	f"Runtime: at line 1 in file {TEST_MODULE_NAME}.py\ndef (num, text)\n\n"
	"Found 1 error (checked 1 module)\n"
	)

[Avasam]

I didn't notice the failing CI. Thanks for letting me know. I actually went and searched through the entire codebase for any instance of "at line". And updated them (which includes docs).

I've also noticed that technically there could be a line number without a file, so I've updated for that case as well.