fmt, strconv: document that exponent is always two digits
Except for %b where it is only one.
Fixes #70862
Change-Id: Ic423a799b73bfa534f4083f6544bb9cd639fef06
Reviewed-on: https://go-review.googlesource.com/c/go/+/636915
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>