docs: add link to lite lab

Author: datakurre

_templates/lite-demo.html

@@ -9,7 +9,7 @@ <h2>DEMO</h2>
   /> in...</em>
   </div>
   <form
-    action="{{ pathto('_/lab/index.html?path=example.ipynb', 1) }}"
+    action="{{ pathto('_/lab/index.html?path=Example.ipynb', 1) }}"
     target="_blank"
     class="demo"
   >
@@ -20,7 +20,7 @@ <h2>DEMO</h2>
       value="JupyterLab"
       class="launch-demo"
     />
-    <input name="path" type="hidden" value="example.ipynb" />
+    <input name="path" type="hidden" value="Example.ipynb" />
     <input name="room" type="hidden" value="" />
   </form>
   <div class="demo-label">