The "branding" XSL template is applied to every text in the Help to
replace %PRODUCTNAME or [$officename] by the correct product name.
It must not escape HTML entities such as < or other.
Reverted previous workaround in xhp page.
Change-Id: I1f7da19ca2899d92917504f162ba497bd9c787bb
Reviewed-on: https://gerrit.libreoffice.org/c/help/+/142555
Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>