DOC: Fix typos and broken formatting
- [ ] closes #xxxx
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

This PR fixes minor typos in the getting started tutorial [How to manipulate textual data?](https://pandas.pydata.org/pandas-docs/stable/getting_started/intro_tutorials/10_text_data.html). I built the documentation to confirm that I fixed the formatting of the Wikipedia link. I also fixed the inconsistent use of "element-wise" versus "element wise".