cmd/compile/internal/noder: begin documenting meta section
Meta is the most fundamental section. To flesh this out, we discuss references. Primitives are briefly mentioned by pointing to pkgbits,
where they will be defined using a similar grammar.
Change-Id: I7abd899f38fad4cc5caf87ebfc7aa1b1985b17d4
Reviewed-on: https://go-review.googlesource.com/c/go/+/671176
Auto-Submit: Mark Freeman <mark@golang.org>
TryBot-Bypass: Mark Freeman <mark@golang.org> Reviewed-by: Robert Griesemer <gri@google.com>