Update link to d3 demo in HelloThere content

editions/tw5.com/tiddlers/HelloThere/Some of the things you can do with TiddlyWiki.tid

@@ -17,4 +17,4 @@ type: text/vnd.tiddlywiki
 * Create a modal wizard (also known as a lightbox) - see SampleWizard
 * Create a slideshow presentation
 * Set up an entire local or online knowledgebase, with a central ~TiddlyWiki file linking to other ~TiddlyWiki files (http://recursos.giffmex.org is a Spanish online example of this)
-* Set up a data visualization using tiddlers as data (see the visualizations at http://tiddlywiki.com/d3demo.html)
+* Set up a data visualization using tiddlers as data (see the visualizations at http://tiddlywiki.com/plugins/tiddlywiki/d3/index.html)