DEPR: resample/groupby.pad/backfill in favor of ffill/bfill
- [x] closes #33396
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit) for how to run them
- [x] whatsnew entry

do we use 'pad' *anywhere* else? if so should deprecate those as well > do we use 'pad' _anywhere_ else? if so should deprecate those as well

`method='pad'` and `method='backfill'` appear in several function like `reindex`, `interpolate` etc. Probably best tackled in subsequent PRs. > > do we use 'pad' _anywhere_ else? if so should deprecate those as well
> 
> `method='pad'` and `method='backfill'` appear in several function like `reindex`, `interpolate` etc. Probably best tackled in subsequent PRs.

kk great