gh-126662: consistent naming for functools._CacheInfo

[tungol]

This MR updates functools._CacheInfo so it's named consistently.

• Issue: Naming consistency for various types #126662

[rhettinger]

Is this really necessary? The CacheInfo result is exposed to the user and this just makes it look weird. Also, changes like this tend to break doc tests.

[tungol]

Would you be okay with keeping the name as CacheInfo but updating the variable to match? I didn't reach for that originally because it removes the private underscore prefix, but it still wouldn't be documented or present in __all__. We can keep _CacheInfo to prevent disruption to anyone using it directly, and it would avoid display weirdness or problems with doc tests.

Is it really necessary either way? I can't say that it's necessary, but name consistency provides small benefits to some runtime and static analysis use cases.

I updated to the alternate approach - I didn't update the use of _CacheInfo as an argument name of _lru_cache_wrapper because then I'd be changing the signature. Let me know if what you think.

[rhettinger]

I'm inclined to leave this as-is. The code has been stable for a long time and does not appear to have caused any real world problems.

ISTM that this falls in the foolish consistency category and that there isn't an actual user issue that needs to be solved. More likely, any change will break code that currently relies on what we have now, Hyrum's Law.

[tungol]

Okay, thanks for considering it.