BUG: Change FutureWarning to DeprecationWarning for inplace setitem with DataFrame.(i)loc
- [X] closes #48673 
- [X] [Tests added and passed](
- [ ] Added [type annotations]
- [ ] All [code checks passed].
- [X] Added an entry in the latest `doc/source/whatsnew/v1.5.3.rst` file.

This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. @aneesh98 during today's community dev meeting we decided to change this warning to `DeprecationWarning` instead of fully removing it. Would you be interested in continuing and making that change? Hi, @mroeschke I am very much interested in completing the change. Hi @mroeschke, just to confirm should be any change to text content of the warnings? > just to confirm should be any change to text content of the warnings?

No change to the text. Also, could you reopen this PR targeting the 1.5.x branch directly? Sorry for the noise, but changing the base branch was a bit trickier than expected. I also addressed the pending comments here.

If CI finishes green, I think this is ready to be merged. If this and #50682 are ready in the next hours, happy to start the release of 1.5.3 tomorrow.

CC: @pandas-dev/pandas-core Push a commit to fix some tests Thanks @aneesh98 for the work on this. As you've seen we finished the last couple of issues, as we need this for the 1.5.3 release which we are going to release today.

And thanks @mroeschke for finishing it.