Fixed Issue #5531 -- Re-arranged placement of shortcut info in keyboard popup

Closes #5531. This is the better version; I closed the previous PR.

Users were confused on how to use keyboard shortcuts because the pop-up
window documentation was confusing. This commit refactors the keyboard
shortcut JS files; the shortcut information is now arranged in a clearer way.

I removed the `help.sort` function. I moved the 2-key keyboard shortcuts to be closer on the upper left corner.