This makesGit.AutoInterrupt andGit.CatFileContentStream transparent aliases to top-level nonpublic_AutoInterrupt and_CatFileContentStream classes in thecmd module.

This does not change the "public" interface. It also does not change metadata relevant to documentation: the__name__ and__qualname__ attributes are set explicitly to the values they had before when these classes were defined nested, so that Sphinx continues to document them (and to do so in full) inGit and asGit.AutoInterrupt andGit.CatFileContentStream.

The purpose of this is to increase readability. TheGit class is big and complex, with a number of long members and various forms of nesting. Since these two classes can be understood even without reading the code of theGit class, moving the definitions out of theGit class into top-level nonpublic classes will hopefully increase readability and help with maintenance.

I originally intended this as just the first commit of several. But I realized that change is probably the only one that might be controversial. So I figured I'd open a PR for it by itself.

In my view:

• The flatter layout and physical separation makes for easier reading and emphasizes that, even as they are nested classes of theGit class as far as the interface is concerned, these classes are uses by theGit and do not themselves use theGit class.
• The conceptual burden of setting__name__ and__qualname__ to make Sphinx continue working as desired (while still having the metadata at runtime the same as Sphinx claims) is not too big of a conceptual burden.

But whether this is better is a subjective question, so I figured it would be good to get a review.

I have verified that the intended effect in Sphinx documentation--the effect that the classes continue to be presented, in full, as nested classes ofGit, just as they may (and should!) continue to be used when they are accessed both within GitPython and by other code that uses GitPython--is what we get. Specifically:

• I observed this locally,and
• It can be seen in the readthedocs cloud build for this PR, forGit.AutoInterrupt andGit.CatFileContentStream. (They can be compared to the latest release versions of theGit.AutoInterrupt andGit.CatFileContentStream classes.)