internal/goexperiment: fix godoc formatting
In internal/goexperiment fix godoc formatting (list indent, add godoc
links).
In internal/buildcfg fix godoc for Experiment.baseline.
Change-Id: I30eaba60cbf3978a375b50dda19dbb2830903bdb
Reviewed-on: https://go-review.googlesource.com/c/go/+/595915
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Austin Clements <austin@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>