[DOXIASITETOOLS-86] Use a linguisticly proper separator between project name and doc title in HTML title

- Using the hex-decimal entity for en dash (U+2013).

git-svn-id: https://svn.apache.org/repos/asf/maven/doxia/doxia-sitetools/trunk@1553005 13f79535-47bb-0310-9956-ffa450edef68