src, misc: applied gofmt -s -w

Pending CL 113120043.

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/112290043
diff --git a/src/pkg/unicode/utf8/utf8.go b/src/pkg/unicode/utf8/utf8.go
index 0dc859a..253295a 100644
--- a/src/pkg/unicode/utf8/utf8.go
+++ b/src/pkg/unicode/utf8/utf8.go
@@ -372,7 +372,7 @@
 
 // RuneCountInString is like RuneCount but its input is a string.
 func RuneCountInString(s string) (n int) {
-	for _ = range s {
+	for range s {
 		n++
 	}
 	return