cmd/compile: fix comment

Change-Id: I32fd5c36f055fdb1dfe56524085676aa4111089a
Reviewed-on: https://go-review.googlesource.com/20830Reviewed-by: David Chase <drchase@google.com>

src/cmd/compile/internal/gc/esc.go

@@ -775,7 +775,7 @@ func esc(e *EscState, n *Node, up *Node) {
 		}
 		// arguments leak out of scope
 		// TODO: leak to a dummy node instead
-		// go f(x) - f and x escape
+		// defer f(x) - f and x escape
 		escassignSinkNilWhy(e, n, n.Left.Left, "defer func")
 
 		escassignSinkNilWhy(e, n, n.Left.Right, "defer func ...") // ODDDARG for call