Modifies example to make it work

Closes #1554

doc/Type/CallFrame.pod6

@@ -22,20 +22,24 @@ Each frame stores L<annotations>, including the L<file> and L<line> annotations,
 
 Here's a short example that will find the calling routine and prints the package of the caller using the C<callframe> interface.
 
-    for 1..* -> $level {
-        given callframe($level) -> $frame {
-            when $frame ~~ CallFrame {
-                next unless $frame.code ~~ Routine;
-                say $frame.code.package;
-                last;
-            }
-            default {
-                say "no calling routine or method found";
-                last;
+    sub calling-frame() {
+        for 1..* -> $level {
+            given callframe($level) -> $frame {
+                when $frame ~~ CallFrame {
+                        next unless $frame.code ~~ Routine;
+                        say $frame.code.package;
+                        last;
+                }
+                default {
+                        say "no calling routine or method found";
+                        last;
+                }
             }
         }
     }
 
+    calling-frame;
+
 If you just need to trace caller information, L<Backtrace> may provide a better means of getting information. L<CallFrame> contains more information about a specific frame, but provides a tedious interface for enumerating a call stack.
 
 =head1 Methods