doc: if you're adopting Pants, and need to integrate that one weird tool

without an org-custom plugin, Pants does many amazing things. but it seems every organization has that handful of tools to integrate

Bugs closed: 105

Reviewed at https://rbcommons.com/s/twitter/r/1166/
Sync of https://github.com/pantsbuild/pants/commit/f106029d2daa500ff5139c0ec1c8aaf835760798