This change separates the completion formatting functions from the
completion logic. It also simplifies the completion logic by necessary
values per-request into a struct that is used throughout.
Change-Id: Ieb6b09b7076ecf89c8b76ec12c1f1c9b10618cfe
Reviewed-on: https://go-review.googlesource.com/c/tools/+/173779
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
