API: `NaTType` and `NAType` are in inconsistent packages

[Dr-Irv]

If you are adding type checking to your application, you may need access to NaTType and NAType. But their locations are in inconsistent packages. The following imports work:

from pandas._libs import NaTType
from pandas._libs.missing import NAType

Should NAType be in pandas._libs if NaTType is?

Note - we don't document these two types, but we use those types in pandas-stubs so if someone was looking at the stubs and wanted to include typing in user code, then the difference in imports would look odd.

Another option is to add these to pandas.api.typing . Would like opinion of @rhshadrach on that.

[rhshadrach]

Adding to typing makes sense to me.