Improve cal-tex-cmd usage

Improve cal-tex-cmd usage

* lisp/calendar/cal-tex.el (cal-tex-cursor-filofax-year)
(cal-tex-cursor-week, cal-tex-cursor-week2)
(cal-tex-cursor-week-iso, cal-tex-cursor-week-at-a-glance)
(cal-tex-cursor-filofax-2week, cal-tex-cursor-filofax-week)
(cal-tex-cursor-filofax-daily, cal-tex-cursor-day)
(cal-tex-insert-preamble, cal-tex-b-document)
(cal-tex-e-document, cal-tex-b-center, cal-tex-e-center):
Improve cal-tex-cmd usage.