feat: apply margin to osd-margin-y

The margins were already set for `osc-margins` and
`user-data/osc/margins`, but osd messages have their own properties
`osd-margin-y` and `osd-margin-x`.
Offsetting `osd-margin-y` by our margin prevents overlap of osd messages
with the GUI.

scripts/uosc.lua

@@ -170,6 +170,8 @@ config = {
 	-- native rendering frequency could not be detected
 	render_delay = 1 / 60,
 	font = mp.get_property('options/osd-font'),
+	osd_margin = mp.get_property('osd-margin-y'),
+	osd_alignment = mp.get_property('osd-align-y'),
 	types = {
 		video = split(options.video_types, ' *, *'),
 		audio = split(options.audio_types, ' *, *'),
@@ -478,7 +480,12 @@ function update_margins()
 	state.margin_bottom = bottom
 
 	utils.shared_script_property_set('osc-margins', string.format('%f,%f,%f,%f', 0, 0, top, bottom))
-	mp.set_property_native("user-data/osc/margins", { l = 0, r = 0, t = top, b = bottom })
+	mp.set_property_native('user-data/osc/margins', { l = 0, r = 0, t = top, b = bottom })
+
+	local osd_margin = 0
+	if config.osd_alignment == 'bottom' then osd_margin = round(bottom * 720)
+	elseif config.osd_alignment == 'top' then osd_margin = round(top * 720) end
+	mp.set_property_native('osd-margin-y', osd_margin + config.osd_margin)
 end
 function create_state_setter(name, callback)
 	return function(_, value)