doc/initial: remove fixed-width spacing notice
Ever since CL 362015 in 2021 it hasn't been necessary to set
"fixed-width phrases with non-fixed-width spaces" because the site CSS
now takes care of this typesetting convention.
Change-Id: Id84f711b65cddf389dc485aa362b23c9c531cbfd
Reviewed-on: https://go-review.googlesource.com/c/go/+/638565
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Auto-Submit: Austin Clements <austin@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>