cmd/compile/internal/syntax: use strings.TrimPrefix in typeOf

Change-Id: I38c2a1afa1684b069522cd1b74529ae10f019ce8
GitHub-Last-Rev: 8c726f1
GitHub-Pull-Request: #63894
Reviewed-on: https://go-review.googlesource.com/c/go/+/539057
Run-TryBot: qiulaidongfeng <[email protected]>
Run-TryBot: Robert Griesemer <[email protected]>
Auto-Submit: Robert Griesemer <[email protected]>
Reviewed-by: Robert Griesemer <[email protected]>
Reviewed-by: qiulaidongfeng <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>

Author: callthingsoff

src/cmd/compile/internal/syntax/nodes_test.go

@@ -322,8 +322,5 @@ func stripAt(s string) (string, int) {
 func typeOf(n Node) string {
 	const prefix = "*syntax."
 	k := fmt.Sprintf("%T", n)
-	if strings.HasPrefix(k, prefix) {
-		return k[len(prefix):]
-	}
-	return k
+	return strings.TrimPrefix(k, prefix)
 }