DEPR: silently ignoring unrecognized timezones
- [x] closes #18702 (Replace xxxx with the GitHub issue number)
- [x] closes #51476
- [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/vX.X.X.rst` file if fixing a bug or adding a new feature.

<s>WIP part is need to figure out #51476 before the deprecation warning will be issued by to_datetime.</s>Update: addressed.
updated to handle strptime inference cc @MarcoGorelli  > WIP part is need to figure out https://github.com/pandas-dev/pandas/issues/51476 before the deprecation warning will be issued by to_datetime.

Looks like you've figured this out? `guess_datetime_format` now raises the deprecation warning > Is the idea just to raise the warning on the pandas side, so that we have control over it and can raise in the future?

yes.

> Looks like you've figured this out? guess_datetime_format now raises the deprecation warning

yes. note was added for 2.0, do we want to backport or move the note? probably better to move the note.  will add to my next Assorted branch thx