Some Projectile Code Cleanup (#22217)

Cleaning up some memory leaks due to projectiles. This one I've actually
made by hand.

code/modules/overmap/overmap_object.dm

@@ -44,6 +44,10 @@
 
 	var/image/targeted_overlay
 
+/obj/effect/overmap/Destroy()
+	QDEL_NULL(targeted_overlay)
+	return ..()
+
 //Overlay of how this object should look on other skyboxes
 /obj/effect/overmap/proc/get_skybox_representation()
 	return

code/modules/projectiles/projectile.dm

@@ -1048,8 +1048,13 @@
 		finalize_hitscan_and_generate_tracers()
 	STOP_PROCESSING(SSprojectiles, src)
 	cleanup_beam_segments()
-	if(trajectory)
-		QDEL_NULL(trajectory)
+	QDEL_NULL(trajectory)
+	firer = null
+	fired_from = null
+	original = null
+	starting = null
+	homing_target = null
+	impacted.Cut()
 	return ..()
 
 /obj/projectile/proc/cleanup_beam_segments()

html/changelogs/hellfirejag-projectile-hard-del.yml

@@ -0,0 +1,4 @@
+author: Hellfirejag
+delete-after: True
+changes:
+  - bugfix: "Fixed a memory leak related to projectiles."