Fix a URL and a typo in docs/API.md
Fix a URL and a typo in docs/API.md

This will conflict with commit dc80e9e5d on the `feature-xml` branch
when that branch is merged to master; that branch's text should win.

PCNI/OpenHMIS,PCNI/OpenHMIS,PCNI/OpenHMIS,PCNI/OpenHMIS