router: Omit unused 2nd value in range loop

router.go

diff --git a/router.go b/router.go
index 1028c03..8d69383 100644
--- a/router.go
+++ b/router.go
@@ -314,7 +314,7 @@
 	}
 
 	// Handle 405
-	for method, _ := range r.trees {
+	for method := range r.trees {
 		if method == req.Method {
 			continue
 		}