[arch-announce] Installation medium with installer

The installation medium now provides a guided [installer](https://archlinux.org/packages/extra/any/archinstall/). This addition to the default method of installation (based on the [installation guide](https://wiki.archlinux.org/index.php/Installation_guide)) is similar to the [other methods](https://wiki.archlinux.org/index.php/Category:Installation_process). If you use this installer, do not forget to mention it when asking for support and also to provide the archinstall log, when asked. URL: https://archlinux.org/news/installation-medium-with-installer/