router: Use http.StatusText

router.go

diff --git a/router.go b/router.go
index 759254b..3a562bd 100644
--- a/router.go
+++ b/router.go
@@ -320,7 +320,10 @@
 		}
 
 		if handle, _, _ := r.trees[method].getValue(req.URL.Path); handle != nil {
-			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+			http.Error(w,
+				http.StatusText(http.StatusMethodNotAllowed),
+				http.StatusMethodNotAllowed,
+			)
 			return
 		}
 	}