Fix styling of `DataFrame` for columns with boolean label
- [x] closes #47838
- [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
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [x] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions. (Not applicable since no new public functions added or signatures modified.)
- [x] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

Summary of changes
* Make the `subset` argument in styling by default a boolean mask indicating where the numerical columns of the data frame are.
* Add new test cases for checking that the expected columns are styled in `.ctx`.
Thanks @bherwerth 