tr2/creatures/dragon: count dragon kill only once

This ensures that the dragon kill is only counted in the statistics
when it is finally defeated rather than after each time it is taken
down.

Resolves LostArtefacts#1771.

docs/tr2/CHANGELOG.md

@@ -53,6 +53,7 @@
 - fixed the game hanging if exited during the level stats, credits, or final stats (#1585)
 - fixed the console not being drawn during credits (#1802)
 - fixed grenades launched at too slow speeds (#1760, regression from 0.3)
+- fixed the dragon counting as more than one kill if allowed to revive (#1771)
 
 ## [0.5](https://github.com/LostArtefacts/TRX/compare/afaf12a...tr2-0.5) - 2024-10-08
 - added `/sfx` command

docs/tr2/README.md

@@ -34,6 +34,9 @@ decompilation process. We recognize that there is much work to be done.
 - fixed the ammo counter being hidden while a demo plays in NG+
 - fixed the game hanging if exited during the level stats, credits, or final stats
 
+#### Statistics
+- fixed the dragon counting as more than one kill if allowed to revive
+
 #### Visuals
 
 - fixed TGA screenshots crashing the game

src/tr2/game/gun/gun_misc.c

@@ -312,7 +312,8 @@ void __cdecl Gun_FindTargetPoint(
 void __cdecl Gun_HitTarget(
     ITEM *const item, const GAME_VECTOR *const hit_pos, const int32_t damage)
 {
-    if (item->hit_points > 0 && item->hit_points <= damage) {
+    if (item->hit_points > 0 && item->hit_points <= damage
+        && item->object_id != O_DRAGON_FRONT) {
         g_SaveGame.statistics.kills++;
     }
     Item_TakeDamage(item, damage, true);

src/tr2/game/objects/creatures/dragon.c

@@ -69,6 +69,7 @@ static void M_MarkDragonDead(const ITEM *const dragon_back_item)
     const ITEM *const dragon_front_item = Item_Get(dragon_front_item_num);
     CREATURE *const creature = dragon_front_item->data;
     creature->flags = -1;
+    g_SaveGame.statistics.kills++;
 }
 
 static void M_PushLaraAway(