CLN: Update old string formatting to f-string
- [x] contributes to #29547 
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Updates:
 pandas/core/ops/array_ops.py
 pandas/core/ops/dispatch.py
 pandas/core/ops/docstrings.py
 pandas/core/ops/invalid.py
 pandas/core/ops/methods.py
 pandas/core/ops/roperator.py

@thepaullee can you have a look at the CI please? Seems like some things are broken. Thanks @thepaullee!

Do the maintainers have a preferred style for the changes introducing temporary variables just for f-strings? For example, https://github.com/pandas-dev/pandas/pull/30631/files#diff-f91291af4cee29af665968c2ffd05013R105-R106 isn't an obvious improvement to me.