Drivers can provide #startframe, #endframe similar to #frame

Currently, Blender provides an automatic driver if we use #frame in any input field. Similarly, it would be useful to provide #startframe, #endframe. This is useful for cases where i want to automatically adjust the timing of my animation in NodeTrees such as Shaders or GeometryNodes.

Currently, we can do it by copying-pasting the drivers from StartFrame and EndFrame in the Timeline.