use userdata

[github-actions[bot]]

use userdata https://github.com/boozook/playdate/blob/a8785842ba04674c8eba6a52391cb041ccdcfd59/api/sound/src/player/fp/mod.rs#L235

Source of this issue

	#[doc(alias = "sys::ffi::playdate_sound_fileplayer::setFinishCallback")]
	pub fn set_finish_callback(&self, callback: sndCallbackProc) {
		let f = self.api().set_finish_callback();
		// TODO: use userdata
		unsafe { f(self.0, callback, core::ptr::null_mut()) }
	}

	/// Equivalent to [setLoopCallback](sys::ffi::playdate_sound_fileplayer::setLoopCallback)
	#[doc(alias = "sys::ffi::playdate_sound_fileplayer::setLoopCallback")]
	pub fn set_loop_callback(&self, callback: sndCallbackProc) {
		let f = self.api().set_loop_callback();
		// TODO: use userdata
		unsafe { f(self.0, callback, core::ptr::null_mut()) }
	}

	/// Changes the volume of the [`Player`] to `left` and `right` over a length of `len` sample frames,