update_aliases

Updates the child modules & classes by replacing the ones that are aliases through a constant.

The aliased module/class is replaced in the children and in RDoc::Store#modules_hash or RDoc::Store#classes_hash by a copy that has RDoc::ClassModule#is_alias_for set to the aliased module/class, and this copy is added to #aliases of the aliased module/class.

Formatters can use the non_aliases method to retrieve children that are not aliases, for instance to list the namespace content, since the aliased modules are included in the constants of the class/module, that are listed separately.