Update getPlugin docs
Update getPlugin docs

Summary: Per title.

Reviewed By: jknoxville

Differential Revision: D13304655

fbshipit-source-id: 8f9e78dbee043e749b1fdd2d4a540eeece66734b

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper