ENH: Add annotations for np.core._type_aliases

[BvB93]

This PR adds annotations for the two dictionaries in np.core._type_aliases:

• sctypes
• sctypeDict

Besides aforementioned dictionaries there is also the allTypes dict.
It doesn't appear to be exposed to the main numpy namespace though and is therefore ignored.

[eric-wieser]

Suggested change

	others: List[type]
	others: List[Type[generic]]

I think is accurate?

[eric-wieser]

Nope, I'm wrong. Seems like a good argument to never use sctypes to me, but that's out of scope for this PR...

[eric-wieser]

Besides aforementioned dictionaries there is also the allTypes dict.
It doesn't appear to be exposed to the main numpy namespace though and is therefore ignored.

You're correct, only its contents are exposed:

numpy/numpy/core/_type_aliases.py

Lines 7 to 9 in e0d27e3

	.. data:: allTypes
	A dictionary of names to types that will be exposed as attributes through
	``np.core.numerictypes.*``

numpy/numpy/core/numerictypes.py

Lines 495 to 498 in e0d27e3

	# Now add the types we've determined to this module
	for key in allTypes:
	globals()[key] = allTypes[key]
	__all__.append(key)

[mattip]

Thanks @BvB93