Support `typing.get_type_hints(partial(fn, ...))` by 'unwrapping' the `partial`, and discarding hints for bound arguments

We added this to Hypothesis' get_type_hints() helper a few years ago, and while most of that function is clearly not suitable to upstream, it struck me recently that "works with functools.partial" could quite reasonably be added to the stdlib function.

It's also plausible that the typing module prefers to avoid calling inspect.signature, though I don't have a great sense of how to determine which parameters have been bound without getting the signature of the partial object. In any case, the implementation need not be the same as in Hypothesis, although as the author you're welcome to use that code if you'd like.

Inizia leggendo l’implementazione esistente di typing.get_type_hints e l’helper di Hypothesis referenziato in hypothesis-python/src/hypothesis/internal/compat.py. Verifica come functools.partial e inspect.signature espongono gli argomenti associati, quindi definisci test che dimostrino che i partial vengono scomposti e che le annotazioni degli argomenti associati vengono scartate. Il lavoro è completato quando il comportamento è coperto senza compromettere i casi esistenti di get_type_hints.