`inspect.formatannotation` should use fully qualified name for type aliases

[JelleZijlstra]

Feature or enhancement

Bug description:

This is inconsistent:

>>> import inspect
>>> type T = int
>>> class C: pass
... 
>>> inspect.formatannotation(T)
'T'
>>> inspect.formatannotation(C)
'__main__.C'

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-157954: Improve type alias support in inspect.formatannotation #157956