Prevent emission of type aliases in root module for inner types

 * Emit aliases in the nearest ancestor module if the parent is not a
   module, rather than in the root module
 * If an alias would refer to itself, don't emit it (this is really a
   workaround for the fact that names are sometimes not unique enough,
   e.g. the header in #2056 produces two items called f_iterator)

Author: jbg

bindgen/ir/context.rs

@@ -791,7 +791,6 @@ If you encounter an error missing from this list, please file an issue or a PR!"
                     item.id(),
                     ancestor_id
                 );
-
                 module.children_mut().insert(item.id());
                 return;
             }