New review comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/53017#discussion_r1844992770

Comment:
```suggestion
The openttd package automatically installs the add-on packages openttd-opengfx,
openttd-opensfx and openttd-openmsx. This will change in a future update. Mark 
the packages manually installed if you wish to continue using these add-ons.
```