go/analysis/cmd/vet: remove pkgfact, findcall analyzers

The suite used by this tool matters to GOROOT/src/cmd/vet/all and the
'vetall' builder.  Add a comment to this effect.

Change-Id: I2e16eb670b03a7bae8224625baaebd1298e2424c
Reviewed-on: https://go-review.googlesource.com/c/150040
Reviewed-by: Michael Matloob <matloob@golang.org>
diff --git a/go/analysis/cmd/vet/vet.go b/go/analysis/cmd/vet/vet.go
index db8180b..d00fb64 100644
--- a/go/analysis/cmd/vet/vet.go
+++ b/go/analysis/cmd/vet/vet.go
@@ -25,13 +25,11 @@
 	"golang.org/x/tools/go/analysis/passes/cgocall"
 	"golang.org/x/tools/go/analysis/passes/composite"
 	"golang.org/x/tools/go/analysis/passes/copylock"
-	"golang.org/x/tools/go/analysis/passes/findcall"
 	"golang.org/x/tools/go/analysis/passes/httpresponse"
 	"golang.org/x/tools/go/analysis/passes/loopclosure"
 	"golang.org/x/tools/go/analysis/passes/lostcancel"
 	"golang.org/x/tools/go/analysis/passes/nilfunc"
 	"golang.org/x/tools/go/analysis/passes/nilness"
-	"golang.org/x/tools/go/analysis/passes/pkgfact"
 	"golang.org/x/tools/go/analysis/passes/printf"
 	"golang.org/x/tools/go/analysis/passes/shift"
 	"golang.org/x/tools/go/analysis/passes/stdmethods"
@@ -44,6 +42,10 @@
 )
 
 func main() {
+	// This suite of analyzers is applied to all code
+	// in GOROOT by GOROOT/src/cmd/vet/all. When adding
+	// a new analyzer, update the whitelist used by vet/all,
+	// or change its vet command to disable the new analyzer.
 	multichecker.Main(
 		// the traditional vet suite:
 		asmdecl.Analyzer,
@@ -69,8 +71,8 @@
 		unusedresult.Analyzer,
 
 		// for debugging:
-		findcall.Analyzer,
-		pkgfact.Analyzer,
+		// findcall.Analyzer,
+		// pkgfact.Analyzer,
 
 		// uses SSA:
 		nilness.Analyzer,