internal/number: fix some Pattern bugs Change-Id: I8eb62939e8a26f1ba39c8a240e676c43eac0de8e Reviewed-on: https://go-review.googlesource.com/45095 Run-TryBot: Marcel van Lohuizen <mpvl@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Nigel Tao <nigeltao@golang.org>