Skip the same of outside of nested namespace

In the code below, the fullname of A::B is A::B,
but it's treated as A::A::A::B now.

module A
  class A::B
  end
end

This commit fixes it.

Author: aycabta

lib/rdoc/parser/ruby.rb

@@ -376,7 +376,11 @@ def get_class_or_module container, ignore_constants = false
       unless :on_const == name_t[:kind] || :on_ident == name_t[:kind]
         raise RDoc::Error, "Invalid class or module definition: #{given_name}"
       end
-      given_name << '::' << name_t[:text]
+      if prev_container == container and !ignore_constants
+        given_name = name_t[:text]
+      else
+        given_name << '::' << name_t[:text]
+      end
     end
 
     skip_tkspace false