Summary:
This mirrors the clang-format config used by fbsource to Yoga.
They are pretty similar, except for an annoying habit where Yoga's previous forced small functions in headers to be a a single line, so you would get a combination of multiline and single line functions next to each other which are hard to read. That is what motivated this change.
It also enforces header ordering (yay). I don't think we have any side-effect causing headers, so this should be safe.
Reviewed By: yungsters
Differential Revision: D49248994
fbshipit-source-id: 66998395e7c0158ff9d9fb1bee44e8401bdd8f21
f9c2c27d33