Feature request: popup key

[fehmud]

Hello,

thank you for sharing this useful package.

Would it be possible to have a popup key? I mean a key that would show the Guide Key menu. For instance, let's say that the user configures <f5> as popup key for Guide Key. Then, typing C-x r <f5> would show the bindings for C-x r. Emacs already does something similar with C-h, but the output of Guide Key is cleaner.

[stardiviner]

+1