links containing square brackets are treated differently than by mediawiki

[larsjsol]

It seems like mwlib treats links containing triple brackets a bit
different than Mediawiki.

For example: "[[WP:IPA for German|[ˈalbɐt ˈaɪnʃtaɪn]]]" is rendered
like this
start_link[ˈalbɐt ˈaɪnʃtaɪn]end_link
by the Wikipedia sandbox, while parser.ParseString() creates this tree:

NamespaceLink target=u'WP:IPA for German' ns=4
u'[\u02c8alb\u0250t \u02c8a\u026an\u0283ta\u026an'
u']\n'

(with the right square bracket is outside the link)

If the link text is removed, like this "[[[ˈalbɐt ˈaɪnʃtaɪn]]]",
Wikipedia displays it as regular text while ParseString creates a
tree that resembles the one above.

I've created a tiny patch that
edit: dosn't work as advertised, sorry.