@phosek mentioned others might want it reST for consistency. As I
personally do not like Markdown at all and just did the "usual GitHub
read-me thing" out of habit, I am more than happy to oblige.
Also fix the typos found in the original.
Reviewed By: phosek, lebedev.ri
Differential Revision: https://reviews.llvm.org/D116524
John Ericson