ENH: updated str_is_numeric(), allows floats
- [X] closes #60750 
- [X] Tests added and passed
- [X] All code checks passed
- [X] Added type annotations 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.

Thanks for the pull request.

The original issue is not a bug and only a doc improvement is required which I believe is being addressed by #60960 Thanks for the PR but the original issue has been addressed by https://github.com/pandas-dev/pandas/pull/60960, so closing.