fixes the 'Pattern involving a subquery' example, as per #136

Author: hartig

spec/index.html

@@ -8840,8 +8840,11 @@ <h4>Examples of Mapped Graph Patterns</h4>
               Join(<br>
               &nbsp;&nbsp; BGP(?s :p ?o) ,<br>
               &nbsp;&nbsp; ToMultiSet(<br>
-              &nbsp;&nbsp;&nbsp;&nbsp; Distinct(Project(BGP(?o ?p ?z), {?o})) )<br>
-              &nbsp;&nbsp; )
+              &nbsp;&nbsp;&nbsp;&nbsp; Distinct( <br>
+              &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Project( ToList(BGP(?o ?p ?z)), {?o} ) <br>
+              &nbsp;&nbsp;&nbsp;&nbsp; ) <br>
+              &nbsp;&nbsp; ) <br>
+              )
             </div>
           </div>
         </section>