Update SMW_LanguageZh_tw.php

Translation update kindly provided by [Linforest](https://semantic-mediawiki.org/wiki/User:Linforest)
I believe that this file is currently a piece of dead code since this commit https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/c299d3435bac9f31baf25ea811af9e775edfffe6 removed its usage for the time being?