CLN: index related attributes on Series/DataFrame
Followup to #31126. IMO the current approach to adding the index related class attributes is too indirect and therefore unnecessary difficult to follow. Just adding the class attributes directly on the relevant class makes reading the code easier, IMO.

Notice that the types are already defined in pandas/core/generic.py:304-316.
Ok, I've made them strings/ints. Yea definitely find this easier to follow as well Thanks @topper-123 