Remove no_type_check_decorator from _typing_names

[Daraan]

Resolves: #700

Tested with 3.15.0a4

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.74%. Comparing base (a7610ef) to head (adf7fc9).

@@            Coverage Diff             @@
##             main     #723      +/-   ##
==========================================
- Coverage   97.38%   96.74%   -0.64%     
==========================================
  Files           3        3              
  Lines        7689     7690       +1     
==========================================
- Hits         7488     7440      -48     
- Misses        201      250      +49     

Flag	Coverage Δ
3.10	?
3.10.4	88.98% <100.00%> (+<0.01%)	⬆️
3.11	88.21% <100.00%> (+<0.01%)	⬆️
3.11.0	87.45% <100.00%> (+<0.01%)	⬆️
3.12	?
3.12.0	88.15% <100.00%> (+<0.01%)	⬆️
3.13	?
3.13.0	82.39% <100.00%> (+<0.01%)	⬆️
3.14	?
3.9	?
3.9.12	89.69% <100.00%> (+<0.01%)	⬆️
pypy3.10	88.81% <100.00%> (+<0.01%)	⬆️
pypy3.11	88.07% <100.00%> (+<0.01%)	⬆️
pypy3.9	89.52% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/typing_extensions.py	93.09% <100.00%> (-0.86%)	⬇️

... and 1 file with indirect coverage changes

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[srittau]

This is technically a breaking change. I wonder whether we shouldn't add a small stub for this for Python 3.15+, so that importing that name doesn't break.

[srittau]

Since this was never implemented by any type checkers as far as I know, we could even skip the import for all Python versions and just add something like (pseudo-code):

def __getattr__(name):
    if name == "no_type_check_decorator":
        # print deprecation warning
        return lambda f: f

or just

@deprecated("...")
def no_type_check_decorator(f):
    return f

[JelleZijlstra]

I think this is fine as is. It's OK if behavior changes depending on the Python version.