scripts: remove TODO about building third party programs

`go build ./...` does indeed compile and link main packages,
it just does not move the resulting binaries anywhere permanent
like `go install` does.

As such, the TODO isn't relevant; the fact that we build all packages
inside each module means we are already linking any binaries matched via
`./...` from the module root.

We don't run any of the binaries, which would catch panics at run-time,
but we already have a note at the top about using `garble test`.

scripts/check-third-party.sh

@@ -13,12 +13,6 @@
 # For example, a good example of a project to add is one that has unearthed
 # multiple bugs in garble before, such as Protobuf.
 # Also remember that the standard library already provides significant cover.
-#
-# TODO: note that this script only catches errors when compiling packages,
-# but it will not catch problems that may only arise at link time,
-# such as go:linknames which are not properly obfuscated.
-# Consider building and linking relevant main packages from each project,
-# such as ./cmd/protoc-gen-go for protobuf.
 modules=(
 	# Protobuf helps cover encoding libraries and reflection.
 	google.golang.org/protobuf v1.28.1