Also minor changes to earlier docs.
Many small changes to improve indentation in generated includes.
Added support for matrix math illustrations.
Docs-Preview: https://skia.org/?cl=58500
Bug: skia:6898
Change-Id: I7da58ad55f82d7fd41d19288beb2cd71730fb01f
Reviewed-on: https://skia-review.googlesource.com/58500
Commit-Queue: Cary Clark <caryclark@skia.org>
Reviewed-by: Cary Clark <caryclark@google.com>
Reviewed-by: Cary Clark <caryclark@skia.org>