Set the store attribute for newly created modules

A regression has been introduced between RDoc 6.0.1 and 6.0.2 with
ef958c2 where a new `RDoc::NormalModule` instance is created without
a store associated to it.

This produces an error on generation through SDoc (see zzak/sdoc#124).

Author: robin850

lib/rdoc/parser/ruby.rb

@@ -363,6 +363,7 @@ def get_class_or_module container, ignore_constants = false
       container ||=
         if ignore_constants then
           c = RDoc::NormalModule.new name_t[:text]
+          c.store = @store
           new_modules << [prev_container, c]
           c
         else