Document supported platforms for `Input.get_accelerometer()` and related
Document supported platforms for `Input.get_accelerometer()` and related

This closes #41303.

(cherry picked from commit eee704e6f602440be1e0007201a1eab534b0a9b1)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot