message: videoio: add note about image BGR format VideoWriter::write()
diff: @@ -905,7 +905,7 @@ public:
  /** @brief Writes the next video frame
  - @param image The written frame
  + @param image The written frame. In general, color images are expected in BGR format.
  The function/method writes the specified image to video file. It must have the same size as has
  been specified when opening the video writer.
  