message: Improve front page
diff: @@ -10,7 +10,8 @@ Bril's design tenets include:
  - The tooling is language agnostic. Bril programs are just [JSON][].
  - Bril is typed.
  -See the [language reference](langref.md) for the complete specification of the core.
  +See the [language reference](lang) for the complete language specification and the [tool documentation](tools) for details on the "batteries included" [monorepo][gh].
  [cs6120]: https://www.cs.cornell.edu/courses/cs6120/2019fa/
  [json]: https://www.json.org
  +[gh]: https://github.com/sampsyo/bril
  