runtime/metrics: add ordering line to supported metrics docs
This change adds an additional line explaining the ordering of the
supported metrics list. It's also necessary to ensure "Supported
metrics" is displayed by godoc as a proper header.
This modification does mean the description test, that ensures
descriptions line up with documentation, needs to change slightly
so it it doesn't read this new line as documentation. Make this
new line the line the test uses to decide when to begin.
Change-Id: I654c1c20e97a80ea79c8eb864445153ce91950bf
Reviewed-on: https://go-review.googlesource.com/c/go/+/275852
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>