update pdf doc link

Author: sn6uv

index.html

@@ -54,7 +54,7 @@ <h2>
 
       <p><a href="http://mathics.angusgriffith.com/doc/">Browse online</a></p>
 
-      <p><a href="docs/mathics-0.9.pdf">Download PDF</a></p>
+      <p><a href="docs/mathics-1.0.pdf">Download PDF</a></p>
 
       <h2>
       <a id="support" class="anchor" href="#support" aria-hidden="true"><span class="octicon octicon-link"></span></a>Support</h2>