DEPR: deprecate Index.is_interval
- [ ] progress towards https://github.com/pandas-dev/pandas/issues/50042
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [x] Added an entry in the latest `doc/source/whatsnew/v2.0.0.rst` file if fixing a bug or adding a new feature.

@topper-123 could you review Looks good. The failure looks unrelated, but the ARM tests should be run again just in case.

Like @phofl said in #50178, it may be a while before we merge. I can keep an eye on this getting in in due time, if you want to focus on other things.  cc @jbrockmendel I think we talked about this as well. Haven't followed the deprecations that closely, do you think we can merge new ones? Ideally I'd like to get #49560 and #49715 in before adding new deprecations, but not a huge deal.  Other than that I'm fine with it as long as @mroeschke is. Yeah ideally I would like to get all the old 1.x deprecations out before adding new ones, but that might not be realistic to block given wanting to release 2.0 next month or so.

I would be fine with merging new ones soon as long as we start a new deprecation tracker for 3.0 issue documenting these new ones > lgtm, thanks @ShisuiUzumaki
> 
> @phofl I see there are just few deprecations in #30228 pending enforcement. Are we still waiting for them to merge PRs with new deprecations?
> 
> @ShisuiUzumaki You'll have to merge main and fix the conflicts in what's new before we can merge.

Which branch do I have to merge `main` into? Are you referring to `ShisuiUzumaki:index_dtype_api_deprecation`? But the merge seems to create a lot of errors, I mean that many checks are falling on the GitHub side > I would be fine with merging new ones soon as long as we start a new deprecation tracker for 3.0 issue documenting these new ones

I created #50578 to track new deprecations. I also created #50579 to keep track of deprecations pending enforcement. What it makes sense to me is to have a detailed look at the code base, see what else is pending enforcement, update #50579, and when we're confident we've got everything pending enforcement under control, then we can start merging PRs with new deprecations. @mroeschke @phofl @jbrockmendel is this more or less what you have in mind to hold merging new deprecations before the rest are enforced? To make it easier to verify we don't forget any? Needs a rebase, good to merge afterwards Ping. Can you rebase. > Ping. Can you rebase.

On it! > Ping. Can you rebase.

Could you have a look? Also, I should mention that there were some conflicts in the `.pre-commit-config.yaml` file. YEah, you need to fix the ‘. pre-commit-config.yaml ‘, else looks good and ready to merge. > YEah, you need to fix the ‘. pre-commit-config.yaml ‘, else looks good and ready to merge.

I think it is done There is still a change in '.pre-commit-config.yaml' in this PR? > There is still a change in '.pre-commit-config.yaml' in this PR?

You mean from the main branch? If you go to https://github.com/pandas-dev/pandas/pull/50196/files, you can see there's still a change in the file `.pre-commit-config.yaml`. Can you remove that change. > If you go to https://github.com/pandas-dev/pandas/pull/50196/files, you can see there's still a change in the file `.pre-commit-config.yaml`. Can you remove that change.

Sure! > If you go to https://github.com/pandas-dev/pandas/pull/50196/files, you can see there's still a change in the file `.pre-commit-config.yaml`. Can you remove that change.

Is it good to go now? Yeah, it's good, Thanks @ShisuiUzumaki.