Maybe implement emacs' previous-history-element

[積丹尼 Dan Jacobson]

All I know is in emacs,
let's say we did
^Rgrandma this morning,
and in the afternoon we did
^Rgrandpa.

Well we could do ^R^R to search for grandpa again, and for grandma we
could employ ^R then
> M-p (translated from <escape> p) runs the command
> previous-history-element (found in minibuffer-local-isearch-map),
so maybe readline could benefit from something like that.
Also see emacs' next-history-element.

Of course the name would need to be changed to previous-search or something.