message: updated explanation on flushing
diff: @@ -89,9 +89,9 @@ impl SpriteBatch {
  /// Returns a mutable reference to the sprites.
  ///
  - /// Please note that manually altering items in this slice
  - /// will not automatically invalidate the buffer, you will
  - /// have to manually call `flush()` or `flush_range()` later.
  + /// Unlike with `MeshBatch`, manually calling `flush` after altering sprites
  + /// in this slice is currently unnecessary, as `SpriteBatch` flushes automatically
  + /// on every draw call. This might change in the future though.
  pub fn get_sprites_mut(&mut self) -> &mut [DrawParam] {
  &mut self.sprites
  }
  