update user guide

jupysketch-doc/site/yamlsketcher/index.html

@@ -449,7 +449,7 @@ Comment::= "#" STRING
 </code></pre>
 
 <p>Here is the railroad grammar diagram:</p>
-<p><a href="/resources/yamlpysketchergrammar.xhtml" target="_blank">Yaml Sketcher Definition</a></p>
+<p><a href="../resources/yamlpysketchergrammar.xhtml">Yaml Sketcher railroad diagram</a></p>
 <p><small><a href="https://bottlecaps.de/rr/ui"target="_blank">[Built thanks]</a></small></p>
 <h2 id="libraries-pysketcher-object-creation-styles-transform">Libraries, Pysketcher Object creation, Styles, Transform</h2>
 <h3 id="libraries">Libraries</h3>