bug#43644: Double quote missing from exec-shell-cmd button command when run

[Natalie Jones]

I'm using hyperbole 7.1.3 on Emacs 26.1 on Debian buster.

To reproduce

1. Create new personal button file

2. Create a new explicit button, action type: exec-shell-command, shell 
cmd: notify-send "test", select no for the rest of the questions

3. Activate the button

What you see:

notify-send "test

What you should see:

notify-send "test"


The second double quote is missing for some reason and the notification 
won't send.