send cancel symbol in case of reset with cancel

src/shellmatta_ymodem.c

@@ -526,6 +526,8 @@ void shellmatta_ymodem_reset(shellmatta_handle_t handle, bool doCancel)
     /* call cancel callback function */
     if (doCancel)
     {
+        /* send cancel symbol */
+        shellmatta_ymodem_control(handle, YMODEM_CA);
         if (shellmatta_ymodem_callbacks.yModemCancelCallback != (void*)0u)
         {
             shellmatta_ymodem_callbacks.yModemCancelCallback();