Improve Mountable Component docs page
Improve Mountable Component docs page

Summary: TSIA

Reviewed By: adityasharat

Differential Revision: D39442689

fbshipit-source-id: 1b0ce115508a831f153c59ade24b14acc32c5ce7

facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho