DOC: Added documentation for ImportError's
…stall.rst

- [x] closes #29399 
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

I've made the changes you've mentioned! While building on my system, I didn't face any issues, but while building it here, I'm unable to find the reason for the build failure. Could you help me out @datapythonista ? @datapythonista Can you check if this can be merged? All the checks have passed!
Thanks! Thanks @gonemad97 