TableLoader is missing information on TableLoader.subarray in docs

[aknierim]

Please describe the use case that requires this feature.
There is no mention of the TableLoader.subarray (not to be confused with TableLoader.read_subarray_events) method in the docs.

Describe the solution you'd like
This method is helpful to get the subarray information such as e.g. the camera geometry of any given telescope via TableLoader.subarray.tel[tel_id].camera.geometry and therefore should be included or mentioned in the docs.