Update doc for what is in "about" page

Author: rocky

mathics/doc/documentation/1-Manual.mdoc

@@ -1008,7 +1008,13 @@ Assuming your are running locally or on a host called 'localhost' using the defa
   <dt><url>http://localhost:8000</url>
   <dd>The single-page application; the main page.
   <dt><url>http://localhost:8000/about</url>
-  <dd>A page giving the versions of this package and version information of important software this uses.
+  <dd>A page giving:
+  <ul>
+    <li>the software versions of this package and version information of important software this uses.
+    <li>directory path information for the current setup
+    <li>machine information
+    <li>system information
+  </ul>
   <dt><url>http://localhost:8000/doc</url>
   <dd>An on-line formatted version of the documentation, which include this text. You can see this as a right side frame of the main page, when clicking "?" on the right-hand upper corner.
 </dl>