1.26.0
(feat): Object types with an xml encoding (e.g. TwiML) now generate XML support: to_xml/to_xml_element,
from_xml/from_xml_element, fluent child builders (response.say("Hello", voice: "alice"), with an
add_ prefix when a child tag collides with a field), and preservation of unknown attributes and child
elements (additional_attributes, additional_children, add_child). A REXML-based
Internal::Xml runtime (with DOCTYPE rejection) is emitted only when XML-encoded types exist.