Filled Polygon "remove" sound effect

For when merging points.

Based on CC Attribution 3.0 sound by "stinkhorn"
(see CHANGES.txt & AUTHORS.txt).

docs/AUTHORS.txt

@@ -166,6 +166,11 @@ June 17, 2002 - May 28, 2024
   <https://freesound.org/people/Halleck/>
   <https://www.eliotlash.com/>
  
+  Filled Polygon "remove" sound effect based on "Ruler Twangs.wav"
+  <https://freesound.org/people/stinkhorn/sounds/20199/>.
+  Creative Commons Attribution 3.0 by stinkhorn
+  <https://freesound.org/people/stinkhorn/>
+
   Bloom magic tool
   by Bill Kendrick <bill@newbreedsoftware.com>
   Googly Eyes sound effect: "Torch Crackle.wav"

docs/CHANGES.txt

@@ -26,10 +26,11 @@ https://tuxpaint.org/
           Creative Commons 0 by Kenneth Cooney
           <https://freesound.org/people/Kenneth_Cooney>
           <https://www.kennethcooney.com/>
-        - "JacobsLadderSingle2.flac",
+        - "JacobsLadderSingle2.flac", Creative Commons Attribution 4.0
-          Creative Commons Attribution 4.0 by Eliot Lash
+          by Eliot Lash <https://freesound.org/people/Halleck/>
-          <https://freesound.org/people/Halleck/>
           <https://www.eliotlash.com/>
+        - "Ruler Twangs.wav", Creative Commons Attribution 3.0
+          by stinkhorn <https://freesound.org/people/stinkhorn/>
       Closes https://sourceforge.net/p/tuxpaint/feature-requests/251/
 
   * Magic Tool Improvements:

magic/src/polyfill.c

@@ -41,6 +41,7 @@ char *polyfill_icon_filenames[NUM_TOOLS] = {
 enum {
   SND_PLACE,
   SND_MOVE,
+  SND_REMOVE,
   SND_NEARBY,
   SND_FINISH,
   NUM_SOUNDS
@@ -49,6 +50,7 @@ enum {
 char *polyfill_snd_filenames[NUM_SOUNDS] = {
   "polyfill_place.ogg",
   "polyfill_move.ogg",
+  "polyfill_remove.ogg",
   "polyfill_nearby.ogg",
   "polyfill_finish.ogg",
 };
@@ -471,6 +473,9 @@ polyfill_release(magic_api * api, int which ATTRIBUTE_UNUSED,
           polyfill_pt_y[i] = polyfill_pt_y[i + 1];
         }
         polyfill_num_pts--;
+
+        /* Play "remove" sound effect */ 
+        api->playsound(snd_effects[SND_REMOVE], (x * 255) / canvas->w, 255);
       }
     }