Fix typo in main page documentation
Fix typo in main page documentation

xf22001/libxmlpp,alanxz/libxmlpp,GNOME/libxmlmm,boomuuh/libxml-cpp,GNOME/libxmlmm,dtrebbien/libxmlmm,GNOME/libxmlmm,alanxz/libxmlpp,xf22001/libxmlpp,boomuuh/libxml-cpp,alanxz/libxmlpp,alanxz/libxmlpp,dtrebbien/libxmlmm,xf22001/libxmlpp,GNOME/libxmlmm,boomuuh/libxml-cpp,dtrebbien/libxmlmm