help-insert-xref-button
help-insert-xref-button is an autoloaded compiled Lisp function in `help-mode.el
'.
(help-insert-xref-button STRING TYPE &rest ARGS)
Insert STRING and make a hyperlink from cross-reference text on it.
TYPE is the type of button to use. Any remaining arguments are passed
to the button's help-function when it is invoked.
See `help-make-xrefs'.