Also update doc.

Bug: angleproject:3928
Change-Id: I1134e1fa9338fa95d647502bf62edb42555caec8
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2033487Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>