n/essentialsoftware: also add mangohud to the base system

n/essentialsoftware.md

@@ -175,7 +175,7 @@ bit...
 # Ensure third party Fedora repos are available, this is part of KDE Prompt?
 sudo fedora-third-party enable
 # Layer packages I need on top of the base image.
-sudo rpm-ostree install aircrack-ng android-tools btop clang cronie cronie-anacron darkman duperemove gamescope git-lfs gnome-console haveged htop inxi iucode-tool iwd kate mosh mpv neovim nmap npm pipx pre-commit qrencode rng-tools rubygem-bundler setroubleshoot sshguard steam-devices symlinks syncthing terminus-fonts-console tmux tor torsocks unbound zsh
+sudo rpm-ostree install aircrack-ng android-tools btop clang cronie cronie-anacron darkman duperemove gamescope git-lfs gnome-console haveged htop inxi iucode-tool iwd kate mangohud mosh mpv neovim nmap npm pipx pre-commit qrencode rng-tools rubygem-bundler setroubleshoot sshguard steam-devices symlinks syncthing terminus-fonts-console tmux tor torsocks unbound zsh
 # Remove packages I don't need from the base image. (Challenge to remove
 # nothing failed by using rpmfusion codecs anyway)
 sudo rpm-ostree override remove firefox firefox-langpacks

txt/gamescope.txt

@@ -0,0 +1 @@
+SteamDeck=1 MANGOHUD=0 gamemoderun gamescope --steam --borderless --mangoapp -- %command%