REGR: re-add encoding for read_excel
- [ ] closes #35753
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Needs tests!
> Needs tests!

There were changes to `test_to_excel_output_encoding` in #34464, can that test be updated to cover this.


 Does this do nothing or am I misreading it? Doesn't the excel format already define how to interpret its data? > Does this do nothing or am I misreading it? Doesn't the excel format already define how to interpret its data?

I think it doesn't do what I expected it to do:

It will forward the `encoding` to https://github.com/pandas-dev/pandas/blob/13940c7f3c0371d6799bbd88b9c6546392b418a1/pandas/io/excel/_base.py#L494

but this is the wrong place (`encoding` finally ends up in `TextFileReader` but it seems to be never used there), it should (if we have an Excel file that needs a specific encoding) go to

https://github.com/pandas-dev/pandas/blob/13940c7f3c0371d6799bbd88b9c6546392b418a1/pandas/io/excel/_xlrd.py#L37

since this is the place (or one of the places) where the file is actually opened. After that, all functions seem to operate on strings so there shouldn't be a need for an encoding form there one.

I will put this PR in draft mode until we have an excel file that needs an encoding.

Edit: closed, a future PR might go the route of forwarding the encoding to each "Excel backend" (if there is a need for that)