[Request]: Change keyboard shortcuts to more standard

[Zach DeCook]

> > I don't advocate changing the *main* keystrokes.
> > I just doubt hundreds have internalized ^Q as reverse search.

> Would you have chosen to assign some other function to it?
> If yes, which one?

Wikipedia has a nice table comparing common Desktop Environment keyboard 
shortcuts against readline/emacs shortcuts.
https://en.wikipedia.org/wiki/Control_key#Table_of_examples

I would say in several cases, the readline/emacs shortcuts have become 
more ingrained in me as I used the terminal more and more.
(Also, as background, I have a background using macOS, which keeps many 
of the emacs-style shortcuts with control (and uses command for what 
other desktop environments use control for)).

Here are my suggestions for the time-being:

* ^Q Quit (exit)
* ^O Open file (read file into new buffer)
* ^Z Undo
* ^Y Redo
* ^F Find (whereis)
* ^X not bound
* ^V not bound
* ^W not bound

And the following, non-standard-but-similar-enough shortcuts should be:

* M-Z Suspend (like ^Z)

Probably the most controversial change here is ^F and ^W

^F is "Forward one character" in readline, and many nano users (myself 
included) have muscle memory for ^W (whereis), However, most interfaces 
use ^F for Find (though many also use the vi-like /).

I think this change is necessary as users coming from a desktop 
environment associate ^W with "Close window". With the current (nano 
4.8) behavior, pressing ^W not only does *not* close the window, it also 
deactivates the shortcut needed to close the window (instead, you need 
to trigger cancel first).

Unbinding ^X and ^V have similar motivations: desktop environment users 
expect them to cut and paste, but their current behavior is jarring.
Changing ^X to cut would hurt  users familiar to nano, so unbinding is 
best. Current behavior of ^C is not jarring, so it doesn't need to change.

Setting M-Z to Suspend (removing toggle suspension) is very logical. 
Users who like to suspend are already using it (M-Z ^Z) to suspend, and 
the toggle seems to only exist so that desktop environment users aren't 
frightened when what they thought was "undo" made everything disappear.

This leaves us with the following 'issues'

* ^B "Backward one character" is not parallel with ^F
* ^Y and ^V no longer do pageup and pagedown
* writeout is no longer bound

The first two aren't too much a concern for me. I usually use a keyboard 
with easy access to home, end, pageup, pagedown and the arrow keys (it's 
more comfortable to use them than ^B ^F ^N ^P ^Y ^V).

I can see how writeout could be useful, so something would need to be 
chosen for that (but for most users, ^S Save is sufficient).

-Zach