DOC: add link to benchmarks page in developer docs
- [x] closes #34405
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew  

@jreback 


@jorisvandenbossche happy with this location? thanks @SwordKnight6216 