This patch also adds a <variable> tag and refactors the file 03030303.xhp (Timer function) to ease x-ref.
Change-Id: I90f26234a9632b9d8220cca94fe2ab11fb4f8fa2
Reviewed-on: https://gerrit.libreoffice.org/c/help/+/119256
Tested-by: Jenkins
Reviewed-by: Jean-Pierre Ledure <jp@ledure.be>