Code named after Freddie Mercury: https://en.wikipedia.org/wiki/Freddie_Mercury

If an input stream is available, prioritize that over sessions. find/grep
syntax can be very complex and can be scripted. On the contrary, sessions
can be loaded at runtime and the persistent session can be "restored".

An interesting use case is the listing is done in picker mode from a script
and the user expects to "pick" some entries among the listed search results.

Another important change is - if the user tries to load the "last session"
explicitly by name instead of using the session option _restore_, we should
not overwrite the "last session" ("@") before loading the it.

This reverts commit c074572748.

* Fix rollover bug

Fixes #743

* Snap to edges in no rollover multiline scroll mode

* Style fix

Fixes #743

* Add nerdfont defs file and normalize vars

* some cleanup

* address feedback

* one more spacing issue

* address feedback