GitLab

* picture-xtra.texi (Insert in Picture): Use <next> and <prior>.

* mini.texi (Completion Commands): Decapitalize <next> and <prior>, and
use camel-case for PageUp and PageDown.

* display.texi (Scrolling): Decapitalize <next> and <prior>, and use
camel-case for PageUp and PageDown.

* calendar.texi (Scroll Calendar): Decapitalize <next> and <prior>.

* search.texi (Isearch Scroll): Decapitalize <next> and <prior>.