(a) The title or heading of a rule may be considered in construing the rule.(b) Provisos shall be construed to limit rather than to extend the operation of the clauses to which they refer.(c) Exceptions expressed in a rule shall be construed to exclude all others.(d) The title or heading prefixed to a chapter of rules shall not be considered to control but may be used in construing the rules.(e) A note to a rule or an explanatory comment is not a part of the rule but may be used in construing the rule.