CL 4291070: incorporating rsc's feedback

R=rsc
CC=golang-dev
https://golang.org/cl/4313054

src/cmd/govet/govet.go

@@ -256,7 +256,7 @@ func (f *File) checkPrintf(call *ast.CallExpr, name string, skip int) {
 		return
 	}
 	if lit.Kind == token.STRING {
-		if strings.Index(lit.Value, "%") < 0 {
+		if strings.Contains(lit.Value, "%") {
 			if len(call.Args) > skip+1 {
 				f.Badf(call.Pos(), "no formatting directive in %s call", name)
 			}
@@ -338,7 +338,7 @@ func (f *File) checkPrint(call *ast.CallExpr, name string, skip int) {
 	}
 	arg := args[skip]
 	if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
-		if strings.Index(lit.Value, "%") >= 0 {
+		if strings.Contains(lit.Value, "%") {
 			f.Badf(call.Pos(), "possible formatting directive in %s call", name)
 		}
 	}

src/pkg/go/printer/nodes.go

@@ -515,7 +515,7 @@ func walkBinary(e *ast.BinaryExpr) (has4, has5 bool, maxProblem int) {
 		}
 
 	case *ast.StarExpr:
-		if e.Op == token.QUO {
+		if e.Op == token.QUO { // `*/`
 			maxProblem = 5
 		}
 

src/pkg/go/printer/printer.go

@@ -127,7 +127,7 @@ func (p *printer) internalError(msg ...interface{}) {
 
 
 // escape escapes string s by bracketing it with tabwriter.Escape.
-// Escapes strings pass through tabwriter unchanged. (Note that
+// Escaped strings pass through tabwriter unchanged. (Note that
 // valid Go programs cannot contain tabwriter.Escape bytes since
 // they do not appear in legal UTF-8 sequences).
 //