Added new PointND and PointND_Array type aliases

[chopan050]

Added new InternalPointND, PointND, InternalPointND_Array and PointND_Array` type aliases, because:

• There exist VectorND and VectorND_Array type aliases, but their point equivalents didn't exist.
• New algorithms, such as the ones proposed in the PR Added ConvexHull, ConvexHull3D, Label and LabeledPolygram #3933, might need them.

Links to added or changed documentation pages

https://manimce--3980.org.readthedocs.build/en/3980/reference/manim.typing.html#manim.typing.InternalPointND

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested

[JasonGrace2282]

Looks good to me, thanks!