fix: Fix text for the disable top blocks plugin on the demo page goog…

…le#2081 (google#2092)

Replaced text on line 318 with a better discription for the plugin

gh-pages/_index.html

@@ -315,7 +315,7 @@ <h4>
         Disable Top Blocks
       </h4>
       <p>
-        A plugin that disables all top-level blocks that have a previous connection. Useful for event-driven environments where all code execution must begin from top-level start/event blocks.
+        A plugin that hides the 'Enable' context menu option for orphan blocks. Works with the <code>Blockly.Events.disableOrphans</code> change listener in core.
       </p>
     </div>
   </a>