2017-05-29  Stephen Berman  <stephen.berman@gmx.net>

	Make `todo-toggle-item-highlighting' work on multiline items

	* lisp/calendar/todo-mode.el (todo-hl-line-range): New named
	function, replacing an anonymous function for the sake of
	`describe-variable'.
	(todo-modes-set-2): Use it as buffer-local value of
	hl-line-range-function and remove boundp test of this
	variable, so its value is available on invoking
	`todo-toggle-item-highlighting'.