Add site url to docs

mkdocs.yml

@@ -1,4 +1,5 @@
 site_name: PiGallery2 Documentation
+site_url: https://bpatrik.github.io/pigallery2/
 theme:
   name: material
   palette:
@@ -9,7 +10,10 @@ plugins:
   - glightbox
 
 markdown_extensions:
-  - pymdownx.magiclink
+  - pymdownx.magiclink:
+      repo_url_shorthand: true
+      user_map:
+        github: bpatrik
   - pymdownx.highlight:
       anchor_linenums: true
       line_spans: __span