Implement ZipExtFile in the zipfile type stubs

[CraftSpider]

Adds the ZipExtFile as a stub in zipfile.pyi. Closes #1224

Known issues:

• read1 errors due to incompatible superclass type, however this is how the implementation is written
• python2 errors with name defined differently in superclass, however this is the type actually provided by the implementation

Assistance for the proper resolution of these two issues is welcome.

[JelleZijlstra]

For read1, you'll just have to # type: ignore; that's what we do in a few other places where the real world gives us incompatible overrides.

For name, it looks like it can be both str and unicode in Python 2, but defaults to str. It may be easier to just use name: str.

[CraftSpider]

Alright, thank you. I'll update the PR with those changes

[CraftSpider]

Any updates on this? I understand if people are busy, but also I want to make sure this doesn't fall completely by the wayside

[JelleZijlstra]

Looks like I started a review but never submitted it, sorry for that!

[CraftSpider]

Thanks for the patience, had stuff that took priority over the weekend. Fixed the noted issues

[CraftSpider]

Any updates on the review for this? I'm not sure if there's anything left for me to do

[JelleZijlstra]

Sorry for the delay!