#2668: Make PAGE_DOWN and PAGE_UP navigate sections of the same page.
#2668: Make PAGE_DOWN and PAGE_UP navigate sections of the same page.

lino-framework/lino,lino-framework/lino,lsaffre/lino,lsaffre/lino,lino-framework/lino,lsaffre/lino,lsaffre/lino,lino-framework/lino,lsaffre/lino,lino-framework/lino