all: update vendored golang.org/x/tools

Now that x/tools/go/types/objectpath has been updates to support type
parameters, I ran the following commands to update x/tools inside the
cmd module:

	go get -d golang.org/x/tools@18fa840216958359dc43466f3e70d96add38edbb # main branch
	go mod tidy
	go mod vendor

Updates #48588

Change-Id: Ibebc1ac2f721d6e2eb1a4f6c610918770d4879ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/355012


Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>