Completed cv2.Error and cv2.error types

[Avasam]

I have completed the self-referencing cv2.error (mentioned in #213) and the missing module cv2.Error. I've done so by looking at the content during runtime.

There's still two issues I'm not sure how to fix, suggestions are welcome.

1. Python language server in VSCode reporting Error as Any if imported from cv2:

import cv2
from cv2 import Error
cv2.Error.STS_ASSERT
Error.STS_ASSERT

Although the "Go to Definition" action still works.

2. Pyrigth will report reportMissingModuleSource and Pylint will report no-name-in-module with import cv2.Error:

import cv2.Error
cv2.Error.STS_ASSERT

Pylint is somewhat excepted and can be worked around by adding "cv2" to the extension-pkg-allow-list configuration. Pyright however, I am not sure.

[Avasam]

I figured out my first point, I replaced from cv2 import Error, by

import cv2.Error as Error
__all__ = ["Error"]

and it all references properly now.

As for the second point, I guess if you are going to use import cv2.Error, with Pyright just ignore the error for this line. Since Pyright is right that the source is missing, givent that it's generated.

[Avasam]

Can I get a review on this?

[debonte]

@Avasam, thanks for this change and all your other recent cleanup work in this repo! :)