Summary:
If someone clicks on `Edit on GitHub` to edit a doc for a pull request, for example,
then we should point to `master` instead of `gh-pages`.
> Also fixed some Windows-based line endings. From CRLF to LF.
Test Plan: https://www.facebook.com/pxlcld/pvV2
Reviewers: IslamAbdelRahman, lgalanis, sdong
Reviewed By: sdong
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D63435
2d9d36ea46