TYP: Typing improvements for Index
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
 Add axis to Index.repeat
 Add sort to Index.union
 Add sort to Index.difference
 Add sort and result_name to Index.symmetric_difference
 Add level to Index.isin
 Add start, end, step to Index.slice_locs
 Add loc to Index.delete
 Add axis to Index.argmin
 Add axis to Index.argmax
 Add axis to Index.min
 Add axis to Index.max
 Add dtype to Index.astype
Note: I've discussed [this error](https://github.com/pandas-dev/pandas/actions/runs/9676397917/job/26695859464?pr=59105#step:12:512) with @phofl at pydata meetup. He told me that this error could likely be ignored, probably some pyright issue Seems like pyright meant numpy.integer by "integer". Now everything is passed @phofl  > If you want, you can also add some of these changes to pandas-stubs.
> 
> @Dr-Irv

Yes, a PR in `pandas-stubs` would be welcome.  Some of these methods are already done there, others need updates similar to what is in this PR.
 Thank you @AndreyKolomiets !