Remove out-dated Proguard section from docs
Remove out-dated Proguard section from docs

Reviewed By: muraziz

Differential Revision: D16861871

fbshipit-source-id: fc220d3caa9de54d6d03bca4ec448961507c948f

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