Shorten parts of the quickhelp

Mostly an aesthetic change here
* shortened a couple of the descriptions so everything will fit in less space while still being clear in meaning
* separate binding from descript with a colon, and separate the different bindings just by spaces.  This is like what is seen on the bottom title bar (except two spaces), and is also reflected in other TUI programs, like mutt.

![Quickhelp](https://i.imgur.com/IWPd0VP.png)
![Quickhelp 2](https://i.imgur.com/Q367QCO.png)