ENH: Support For Interval __contains__ Other Interval (#46613)
- [x] closes #46613
- [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
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [x] 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/vX.X.X.rst` file if fixing a bug or adding a new feature.

Apologies for the mess in the history! I suggested @kapiliyer rebase rather than merge and I'm seeing now that the history's in a weird state. Later today I'll work with him to get his branch into a cleaner state. History should be in a saner state now. Apologies again for the trouble! Thanks @kapiliyer! 