minor docs corrections 2

docs/HTML/KMeansVisitor.html

@@ -61,7 +61,7 @@
 KMeansVisitor(std::size_t num_of_iter,
               bool calc_clusters = true,
               distance_func f = [](const T &x, const T &y) -> double {
-                                    `return ((x - y) * (x - y));
+                                    return ((x - y) * (x - y));
                                 })
         </PRE>
         </I>