Make `CopyComPointer` public and add to `ctypes` doc.

[junkmd]

Feature or enhancement

Proposal:

As with COMError in gh-126615 and gh-126686, I think CopyComPointer should also be made public and documented.

Tests covering the behavior of this API have already been added in gh-127183 and gh-127184.

I plan to write documentation based not only on the C implementation source code but also on these tests.

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

#127184

Linked PRs

• gh-127255: Make CopyComPointer public and add to ctypes doc. #127275

[encukou]

Thank you!