Add duck_quack sound (CC BY-SA 3.0) by Jonathon Jongsma...

https://www.xeno-canto.org/62258

README.md

@@ -33,6 +33,7 @@ As of right now, only sounds from *default* mod have been added.
 | [coin][]                          | greenvwbeetle            | CC0          |                         |
 | [cow_moo*][cow_moo]               | JosephSardin             | CC0          |                         |
 | [dog_bark][]                      | ivolipa                  | CC0          |                         |
+| [duck_quack][]                    | Jonathon Jongsma         | CC BY-SA 3.0 |                         |
 | [elephant][]                      | vataaa                   | CC0          |                         |
 | [entity_hit][]                    | sonictechtonic           | CC BY 3.0    |                         |
 | [explosion][]                     | JuveriSetila             | CC0          |                         |
@@ -167,6 +168,7 @@ sounds.horse_neigh(2, {gain=1.0})
 [dig_metal]: https://freesound.org/s/320397/
 [dig_snappy]: https://freesound.org/s/251660/
 [dog_bark]: https://freesound.org/s/328730/
+[duck_quack]: https://www.xeno-canto.org/62258
 [dug_glass.1]: https://freesound.org/s/71947/
 [dug_glass.2]: https://freesound.org/s/97669/
 [dug_glass.3]: https://freesound.org/s/88808/

TODO.txt

@@ -11,7 +11,6 @@ TODO:
 	- wind
 	- tree
 	- leaves
-	- duck
 	- bat
 	- camel
 	- monkey / chimp

changelog.txt

@@ -11,6 +11,7 @@ next
 	- bumble_bee
 	- chicken
 	- clock_tick
+	- duck_quack
 	- grasshopper
 	- jaguar_saw
 	- lion

groups.lua

@@ -98,6 +98,14 @@ sounds.dog_bark = SoundGroup({
 	"dog_bark",
 })
 
+--- Duck quack sounds.
+--
+--  @sndgroup sounds.duck_quack
+--  @snd duck_quack
+sounds.duck_quack = SoundGroup({
+	"duck_quack",
+})
+
 --- Elephant sounds.
 --
 --  @sndgroup sounds.elephant