text/template/parse: remove duplication in peekNonSpace

nextNonSpace has an identical code except the call to
backup at the end.

Change-Id: Iefa5b13950007da38323a800fb6b0ce3d436254b
Reviewed-on: https://go-review.googlesource.com/c/go/+/198277
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

src/text/template/parse/parse.go

@@ -108,13 +108,8 @@ func (t *Tree) nextNonSpace() (token item) {
 }
 
 // peekNonSpace returns but does not consume the next non-space token.
-func (t *Tree) peekNonSpace() (token item) {
-	for {
-		token = t.next()
-		if token.typ != itemSpace {
-			break
-		}
-	}
+func (t *Tree) peekNonSpace() item {
+	token := t.nextNonSpace()
 	t.backup()
 	return token
 }