correct spelling mistake (#1092)

recovery.go

@@ -46,7 +46,7 @@ func RecoveryWithWriter(out io.Writer) HandlerFunc {
 	}
 }
 
-// stack returns a nicely formated stack frame, skipping skip frames.
+// stack returns a nicely formatted stack frame, skipping skip frames.
 func stack(skip int) []byte {
 	buf := new(bytes.Buffer) // the returned data
 	// As we loop, we open files and read them. These variables record the currently