DEPR: 'A' in favour of 'Y'
- [x] closes #54275

xref #54061
deprecated `'A'` in favour of `'Y'`.

* Deprecated `'A'`  in Timedelta units in favour of `'Y'`
* Deprecated alias `'A'`, `'AS'`, `'A-DEC'`, etc. for time series frequencies in favour of `'Y'`, `'YS'`, `'Y-DEC'`, etc.
* Deprecated resolution `'A'`   for Timedelta.resolution_string in favour of `'Y'`
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. @natmokval this seems to be stale and with many conflicts, are you planning to continue work on this PR or should we close it? I guess it may make sense to start over and try to split it in multiple PRs, to make things manageable. > @natmokval this seems to be stale and with many conflicts, are you planning to continue work on this PR or should we close it? I guess it may make sense to start over and try to split it in multiple PRs, to make things manageable.

Thank you, @datapythonista
Sorry, I forgot to close this PR. `Deprecation 'A' in favour of 'Y'` is done in my PR #55252. I will close this one.