pager: rename 'pager.enable' to 'ui.paginate' This aligns with what we do for color (see 7fec37746417). Pager is a central enough notion that having the master config in the [ui] section makes senses. It will helps with consistency, discoverability. It will also help having a simple and clear example hgrc mentioning pager. The previous form of the option had never been released in a non-rc version but we keep it around for convenience. If both are set, 'ui.pager' take priority.