This change adds a new goPackagesModuleGetter, which uses
x/tools/go/packages to query package information for modules requested
by the pkgsite command.
Additionally, add new extension interfaces that allow getters to add
support for search and content invalidation. The go/packages getter uses
these extensions to implement search (via a simple fuzzy-matching
algorithm copied from x/tools), and invalidation via statting package
files.
Along the way, refactor slightly for testing ergonomics.
Updates golang/go#40371
Updates golang/go#50229Fixesgolang/go#54479
Change-Id: Iea91a4d6327707733cbbc4f74a9d93052f33e295
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/474295
TryBot-Result: kokoro <noreply+kokoro@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
Robert Findley