bug#59247: 29.0.50; suggest-key-bindings displays key as command

[Stefan Kangas]

Steps to reproduce:

0. emacs -Q
1. M-x proced RET
2. C-x o
2. M-x proced-mark RET

In *Messages*, I now see:

  You can run the command ‘proced-mark’ with M-x m RET

I expect that this would be something more like:

  You can run the command ‘proced-mark’ with m

I can reproduce this with Emacs 27.1 and current master.