Deprecation: #85735 - Various method and property in DocumentTemplate 

See forge#85735

Description 

The method DocumentTemplate::addStyleSheet() has been marked as deprecated.

The property DocumentTemplate::hasDocheader has been marked as protected as the property is not evaluated anymore in the core.

Impact 

Calling DocumentTemplate::addStyleSheet() will trigger a PHP E_USER_DEPRECATED error.

Using the property DocumentTemplate::hasDocheader will trigger a PHP E_USER_DEPRECATED error.

Affected Installations 

Instances with third party code directly accessing the method or the property.

Migration 

DocumentTemplate::addStyleSheet() can be replaced by using PageRenderer::addCssFile().

The property has no migration available.