TXFANode.AddComment Method
function AddComment(const AValue: AnsiString): TXFANode;
Appends an owned #text node with XMLContentKind=xckComment and returns that child; AValue is the literal UTF-8 payload between the comment delimiters
Entity-looking strings remain literal and comments do not change the parent's aggregate Value
Invalid XML characters, two consecutive hyphens or a trailing hyphen raise EHPDFXFAError before publishing a child
The parent owns the returned node; do not free it separately while it remains in Children