chore: put some more things behind USE_AI

no longer need a game-specific tag here

fgd/bases/Weapon.fgd

@@ -5,14 +5,14 @@
 	spawnflags(flags)  =
 		[
 		1: "Start constrained" : 0
-		2: "Deny player pickup (reserve for NPC)" : 0 [-MOMENTUM]
+		2: "Deny player pickup (reserve for NPC)" : 0 [+USE_AI]
 		4: "Not puntable by Gravity Gun" : 0 [+HL2_ENTITIES]
 		]
 
 	// Outputs
 	output OnPlayerUse(void) : "Fires when the player +uses this weapon."
 	output OnPlayerPickup(void) : "Fires when the player picks up this weapon."
-	output OnNPCPickup[-MOMENTUM](void) : "Fires when an NPC picks up this weapon."
+	output OnNPCPickup[+USE_AI](void) : "Fires when an NPC picks up this weapon."
 	output OnCacheInteraction[+HL2_ENTITIES](void) : "Fires when the player 'proves' they've found this weapon. " +
 		"Fires on: Player Touch, +USE pickup, Physcannon pickup, Physcannon punt."
 	output OnCacheInteraction[-HL2_ENTITIES](void) : "Fires when the player 'proves' they've found this weapon. " +