Document and replace sounds

A few sounds were replaced because I could not find them on freesound.org

README.md

@@ -102,3 +102,16 @@ Other files from Wikimedia Commons:
 RealBadAngel: (CC-BY-4.0)
 
   * Everything else.
+
+
+## Sounds
+
+ * [`bell.ogg`](https://freesound.org/people/bennstir/sounds/81072/) by bennstir, CC 4.0
+ * [`electricity.ogg`](https://freesound.org/people/Halleck/sounds/19486/) by Halleck, CC 4.0 (cut)
+ * [`pageflip1.ogg`](https://freesound.org/people/themfish/sounds/45823/) by themfish, CC 4.0 (cut, slowed down)
+ * `pageflip2.ogg` (derived from `pageflip1.ogg`)
+ * [`trash.ogg`](https://freesound.org/people/OwlStorm/sounds/151231/) by OwlStorm, CC 0 (speed up)
+ * [`trash_all.ogg`](https://freesound.org/people/abel_K/sounds/68280/) by abel_K, Sampling Plus 1.0 (speed up)
+ * [`ui_click.ogg`](https://freesound.org/people/lartti/sounds/527569/) by lartti, CC 0 (cut)
+ * [`ui_morning.ogg`](https://freesound.org/people/InspectorJ/sounds/439472/) by InspectorJ, CC 4.0
+ * [`ui_owl.ogg`](https://freesound.org/people/manda_g/sounds/54987/) by manda_g, Sampling Plus 1.0 (cut)

callbacks.lua

@@ -57,7 +57,7 @@ end)
 local function apply_new_filter(player, search_text, new_dir)
 	local player_name = player:get_player_name()
 
-	minetest.sound_play("click", {to_player=player_name, gain = 0.1})
+	minetest.sound_play("ui_click", {to_player=player_name, gain = 0.1})
 	ui.apply_filter(player, search_text, new_dir)
 	ui.current_searchbox[player_name] = search_text
 	ui.set_inventory_formspec(player, ui.current_page[player_name])
@@ -114,7 +114,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	for i, def in pairs(unified_inventory.buttons) do
 		if fields[def.name] then
 			def.action(player)
-			minetest.sound_play("click",
+			minetest.sound_play("ui_click",
 					{to_player=player_name, gain = 0.1})
 			return
 		end
@@ -179,7 +179,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		end
 	end
 	if clicked_item then
-		minetest.sound_play("click",
+		minetest.sound_play("ui_click",
 				{to_player=player_name, gain = 0.1})
 		local page = unified_inventory.current_page[player_name]
 		local player_creative = unified_inventory.is_creative(player_name)
@@ -219,7 +219,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	if not (fields.alternate or fields.alternate_prev) then
 		return
 	end
-	minetest.sound_play("click",
+	minetest.sound_play("ui_click",
 			{to_player=player_name, gain = 0.1})
 	local item_name = unified_inventory.current_item[player_name]
 	if not item_name then

register.lua

@@ -98,7 +98,7 @@ ui.register_button("misc_set_day", {
 	action = function(player)
 		local player_name = player:get_player_name()
 		if minetest.check_player_privs(player_name, {settime=true}) then
-			minetest.sound_play("birds",
+			minetest.sound_play("ui_morning",
 					{to_player=player_name, gain = 1.0})
 			minetest.set_timeofday((6000 % 24000) / 24000)
 			minetest.chat_send_player(player_name,
@@ -122,7 +122,7 @@ ui.register_button("misc_set_night", {
 	action = function(player)
 		local player_name = player:get_player_name()
 		if minetest.check_player_privs(player_name, {settime=true}) then
-			minetest.sound_play("owl",
+			minetest.sound_play("ui_owl",
 					{to_player=player_name, gain = 1.0})
 			minetest.set_timeofday((21000 % 24000) / 24000)
 			minetest.chat_send_player(player_name,