fixes #824

Author: martin-henz

xml/chapter3/section3/subsection1.xml

@@ -1525,6 +1525,8 @@ display(count_pairs(cycle));
       <SNIPPET>
 	<EXAMPLE>exercise_3_17_solution_example</EXAMPLE>
 	<JAVASCRIPT>
+// solution provided by GitHub user clean99
+	  
 function count_pairs(x) {
     let counted_pairs = null;
     function is_counted_pair(current_counted_pairs, x) {