message: Update RenderTexture constructor documentation
diff: @@ -7,6 +7,9 @@ import Texture from '../textures/Texture';
  * __Hint__: All DisplayObjects (i.e. Sprites) that render to a RenderTexture should be preloaded
  * otherwise black rectangles will be drawn instead.
  *
  + * __Hint-2__: The actual memory allocation will happen on first render.
  + * You shouldn't create renderTextures each frame just to delete them after, try to reuse them.
  + *
  * A RenderTexture takes a snapshot of any Display Object given to its render method. For example:
  *
  * ```js
  