Change "intern" to "internal" in example config

sites.example.yaml

@@ -10,4 +10,4 @@ sites:
 - name: "Other Stuff"
   links:
   - { name: "Webmail", link: "https://mail.farafin.de", icon: envelope }
-  - { name: "Important Stuff", link: "https://topsecret.farafin.de", icon: door-open, intern: true }
+  - { name: "Important Stuff", link: "https://topsecret.farafin.de", icon: door-open, internal: true }