Fixing broken link in user_docs.yml (#85)

Author: ebetica

_data/sidebars/user_docs.yml

@@ -28,7 +28,7 @@ entries:
       output: web, pdf
 
     - title: Adding Content
-      url: /docs-content
+      url: /image-content
       output: web, pdf
 
     - title: User Control