Allow using a different completion pager

[積丹尼 Dan Jacobson]

$ man bash
       page-completions (On)
              If set to On, readline uses an internal more-like pager to  dis‐
              play a screenful of possible completions at a time.

OK, and it looks like:

final.target
first-boot-complete.target
fstrim.service
fstrim.timer
--More--


But if I could use less(1), then I could do
/nerbleblatz
string searches, etc.