2nd attempt: no noIndent for string lists

- slightly better output in general
- extra indentation where we could do without
  (however that seems better for now that not having the indentation
  where it is needed)
- no information is lost, so a future better approach can fix these
  places up again

R=rsc
http://go/go-review/1017050

src/pkg/go/printer/nodes.go

@@ -20,6 +20,7 @@ import (
 const (
 	oneLineFuncDecls = false;
 	compositeLitBlank = false;
+	stringListMode = exprListMode(0);  // previously: noIndent
 )
 
 
@@ -113,7 +114,7 @@ func (p *printer) stringList(list []*ast.BasicLit, multiLine *bool) {
 	for i, x := range list {
 		xlist[i] = x;
 	}
-	p.exprList(noPos, xlist, noIndent, multiLine);
+	p.exprList(noPos, xlist, stringListMode, multiLine);
 }
 
 

src/pkg/go/printer/testdata/expressions.golden

@@ -144,6 +144,43 @@ func _() {
 }
 
 
+const _ = F1 +
+	`string = "%s";`
+		`ptr = *;`
+		`datafmt.T2 = s ["-" p "-"];`
+
+
+const _ = `datafmt "datafmt";`
+	`default = "%v";`
+	`array = *;`
+	`datafmt.T3 = s  {" " a a / ","};`
+
+
+const _ = `datafmt "datafmt";`
+	`default = "%v";`
+	`array = *;`
+	`datafmt.T3 = s  {" " a a / ","};`
+
+
+func _() {
+	_ = F1 +
+		`string = "%s";`
+			`ptr = *;`
+			`datafmt.T2 = s ["-" p "-"];`;
+
+	_ =
+		`datafmt "datafmt";`
+			`default = "%v";`
+			`array = *;`
+			`datafmt.T3 = s  {" " a a / ","};`;
+
+	_ = `datafmt "datafmt";`
+		`default = "%v";`
+		`array = *;`
+		`datafmt.T3 = s  {" " a a / ","};`;
+}
+
+
 func _() {
 	// respect source lines in multi-line expressions
 	_ = a +

src/pkg/go/printer/testdata/expressions.input

@@ -152,6 +152,44 @@ func _() {
 }
 
 
+const _ = F1 +
+	`string = "%s";`
+	`ptr = *;`
+	`datafmt.T2 = s ["-" p "-"];`
+
+
+const _ =
+	`datafmt "datafmt";`
+	`default = "%v";`
+	`array = *;`
+	`datafmt.T3 = s  {" " a a / ","};`
+
+
+const _ = `datafmt "datafmt";`
+`default = "%v";`
+`array = *;`
+`datafmt.T3 = s  {" " a a / ","};`
+
+
+func _() {
+	_ = F1 +
+		`string = "%s";`
+		`ptr = *;`
+		`datafmt.T2 = s ["-" p "-"];`;
+
+	_ =
+		`datafmt "datafmt";`
+		`default = "%v";`
+		`array = *;`
+		`datafmt.T3 = s  {" " a a / ","};`;
+
+	_ = `datafmt "datafmt";`
+	`default = "%v";`
+	`array = *;`
+	`datafmt.T3 = s  {" " a a / ","};`
+}
+
+
 func _() {
 	// respect source lines in multi-line expressions
 	_ = a+

src/pkg/go/printer/testdata/expressions.raw

@@ -144,6 +144,43 @@ func _() {
 }
 
 
+const _ = F1 +
+	`string = "%s";`
+		`ptr = *;`
+		`datafmt.T2 = s ["-" p "-"];`
+
+
+const _ = `datafmt "datafmt";`
+	`default = "%v";`
+	`array = *;`
+	`datafmt.T3 = s  {" " a a / ","};`
+
+
+const _ = `datafmt "datafmt";`
+	`default = "%v";`
+	`array = *;`
+	`datafmt.T3 = s  {" " a a / ","};`
+
+
+func _() {
+	_ = F1 +
+		`string = "%s";`
+			`ptr = *;`
+			`datafmt.T2 = s ["-" p "-"];`;
+
+	_ =
+		`datafmt "datafmt";`
+			`default = "%v";`
+			`array = *;`
+			`datafmt.T3 = s  {" " a a / ","};`;
+
+	_ = `datafmt "datafmt";`
+		`default = "%v";`
+		`array = *;`
+		`datafmt.T3 = s  {" " a a / ","};`;
+}
+
+
 func _() {
 	// respect source lines in multi-line expressions
 	_ = a +