Typo

Co-authored-by: Radu Nichita <[email protected]>

examples/filter_int_iterator.cpp

@@ -25,7 +25,7 @@ struct filtered_int_iterator
     }
 
     // A forward iterator based on iterator_interface usually requires
-    // three user-defined operations.  since we are adapting an existing
+    // three user-defined operations.  Since we are adapting an existing
     // iterator (an int *), we only need to define this one.  The others are
     // implemented by iterator_interface, using the underlying int *.
     filtered_int_iterator& operator++() {