Don't paste the entire command-line into the generated file

This helps us avoid diffs between Bazel-based builds and `go build`-driven builds.

cmd/stringer/stringer.go

@@ -144,7 +144,7 @@ func main() {
 	g.parsePackage(args, tags)
 
 	// Print the header and package clause.
-	g.Printf("// Code generated by \"stringer %s\"; DO NOT EDIT.\n", strings.Join(os.Args[1:], " "))
+	g.Printf("// Code generated by \"stringer\"; DO NOT EDIT.\n")
 	g.Printf("\n")
 	g.Printf("package %s", g.pkg.name)
 	g.Printf("\n")