Added missing 'ambientColor' property.

docs/file-formats.html

@@ -813,6 +813,17 @@ class="p">(</span><span class="s">"res/common/game.scene"</span><span class="p">
 		xref
 	</td>
 </tr>
+<tr>
+	<td>
+		&nbsp; ambientColor = <span class="Non-literal"><span>x, y, z</span></span>
+	</td>
+	<td>
+		[0..1]
+	</td>
+	<td>
+		3 floats
+	</td>
+</tr>
 <tr>
 	<td>
 		&nbsp; activeCamera = <span class="Non-literal"><span>node_id</span></span>