doc: full properties now always have a pipe symbol after their identifier

doc/sample/Person.im

@@ -108,7 +108,7 @@ class Person
     /* Without the lambda synthesis, the property would look like this:
        Note that this is the only time it is legal to access private fields
        via `self` from a lambda. */
-    $ exampleProperty
+    $ exampleProperty |
         get => [ ^self.val ],
         set => [ :x | self.val = x ].