Character sheet: prevent out-of-bounds reads from deadliness_conversion

Before the change, a dark-elf druid thrall with the default point buy would cause the game, when compiled with tbe undefined behavior sanitizer, to crash when displaying the character sheet at the last stage of the birth process.

src/ui-player.c

@@ -825,10 +825,13 @@ static struct panel *get_panel_combat(void) {
 	if (!obj && (player_has(player, PF_UNARMED_COMBAT) ||
 				 player_has(player, PF_MARTIAL_ARTS))) {
 		panel_line(p, COLOUR_L_BLUE, "Melee", "Av.%d,%+d%%",
-				   average_unarmed_damage(player), deadliness_conversion[dam]);
+				   average_unarmed_damage(player),
+				   deadliness_conversion[MAX(dam, 0)]);
 	} else {
-		panel_line(p, COLOUR_L_BLUE, "Melee", "%dd%d,%+d%%", melee_dice,
-				   melee_sides, deadliness_conversion[dam]);
+		panel_line(p, COLOUR_L_BLUE, "Melee", "%dd%d,%c%d%%", melee_dice,
+				   melee_sides,
+				   (dam >= 0) ? '+' : '-',
+				   deadliness_conversion[MIN(ABS(dam), 150)]);
 	}
 	panel_line(p, COLOUR_L_BLUE, "To-hit", "%d,%+d", bth / 10, hit);
 	panel_line(p, COLOUR_L_BLUE, "Blows", "%d.%d/turn",
@@ -844,8 +847,9 @@ static struct panel *get_panel_combat(void) {
 		hit += object_to_hit(obj);
 	}
 
-	panel_line(p, COLOUR_L_BLUE, "Shoot to-dam", "%+d%%",
-			   deadliness_conversion[dam]);
+	panel_line(p, COLOUR_L_BLUE, "Shoot to-dam", "%c%d%%",
+			   (dam >= 0) ? '+' : '-',
+			   deadliness_conversion[MIN(ABS(dam), 150)]);
 	panel_line(p, COLOUR_L_BLUE, "To-hit", "%d,%+d", bth / 10, hit);
 	panel_line(p, COLOUR_L_BLUE, "Shots", "%d.%d/turn",
 			   player->state.num_shots / 10, player->state.num_shots % 10);