Special handling of anchors

Anchor ids/names need to follow a strict syntax in Doxia, therefore both anchor names (<a name="...">) as well as internal link targets (<a href="...") are automatically adjusted to comply with that syntax. Further details in DoxiaUtils.encodeId(…).

In order to leave internal link targets (i.e. ones not starting with a scheme) unprocessed use attribute rel with value external like this

<a href="testpage#specialanchor()" rel="external">...</a>

Otherwise the fragment specialanchor() would be converted as ( and ) are not valid in Doxia IDs.