Repair several minor breakages

Repair several minor breakages

* lisp/calendar/calendar.el (calendar-event-buffer): New
function.
(calendar-cursor-to-date, calendar-other-month):

* lisp/calendar/holidays.el (calendar-list-holidays)
(calendar-mark-holidays):

* lisp/calendar/lunar.el (calendar-lunar-phases): Use that
function to derive event windows, in case these commands are
being called from the menu bar.

* lisp/doc-view.el (doc-view-tool-bar-map): Fix typo in help
text.