Fix typo in docs refman-debug_print_metastack.md

doc/refman-debug_print_metastack.md

@@ -14,7 +14,7 @@ label:type_name[cmd]...[cmd]
 
 where
 
-- `label` is the label of the handler (given by the user or automatically generated by `OneShot::Handle`)
+- `label` is the label of the handler (automatically generated or given by the user when calling `handle` or `wrap`)
 
 - `type_name` is the `typeid()::name` of the handler class,