docs: fix broken sidebar link and clean build cache

Author: xrissoula

docs/Getting-Started/polykey-cli/running-the-agent-with-systemd.md

@@ -18,13 +18,9 @@ were introduced:
   environments.
 
 These modules utilize `systemd`, a service manager used in most Linux
-distributions.
-git st
-:::note Note 
-On NixOS, Polykey is not configured through .service files, but
-instead through the Home Manager or Nix configuration. See the NixOS integration
-section below. 
-:::
+distributions. git st :::note Note On NixOS, Polykey is not configured through
+.service files, but instead through the Home Manager or Nix configuration. See
+the NixOS integration section below. :::
 
 ## What is systemd?