Add the command identifier to GetHighlightCommand

This allows us to interact with the command with other UI functions.

section/GetHighlightCommand.cpp

@@ -21,6 +21,7 @@ int UIGetHighlightCommand(lua_State *L) {
  lua_push(L, "x", command->pos.x);
  lua_push(L, "y", command->pos.y);
  lua_push(L, "z", command->pos.z);
+ lua_push(L, "commandId", commandId);
  auto targetId = command->targetId;
  if (targetId != 0xF0000000) {
  char buf[16];