This adds a link from the main docs page back to the README where
I have previously added a list of useful resources.
To that list, I've added a link to my recent llvm blog post.
Though I doubt that many people will land here directly, I thought it
odd that we didn't have one we can at least reference in response to questions.
The intro I've copied from the programmer's reference and added a simple
example. Then some links to resources and tools, which is the main
reason to have this page.