Support `__getattr__` method in AC

[StanFromIreland]

I tried to convert the function to Argument Clinic, but it failed, oh!

Error in file 'Modules/zlibmodule.c' on line 2019:
'__getattr__' is a special method and cannot be converted to Argument Clinic!

Originally posted by @vstinner

Would this be a valid feature request for AC or it’s somehow impossible?

Originally posted by @merwok in #140130 (comment)

Linked PRs

• gh-140382: Add support for __getattr__ method to Argument Clinic #140376