New comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/pull/25511#issuecomment-780574887

Comment:
@bugcrazy please don't tag me in multiple places, I did see your comment here.

Their cmake install includes all the files, as you can see here:

```
➜ xbps-query -Rf devilutionX
/usr/bin/devilutionx
/usr/share/applications/devilutionx.desktop
/usr/share/diasurgical/devilutionx/README.txt
/usr/share/fonts/truetype/CharisSILB.ttf
/usr/share/icons/hicolor/512x512/apps/devilutionx.png
/usr/share/licenses/devilutionX/LICENSE
```

I removed the INSTALL.msg because they should be used for warnings about package changes or similar, not for general package information. For that, we can use a README.voidlinux. If you want to open a PR to add such a file, I will gladly merge it.