self-insert-command could display more details

[mattiasdrp]

Hi, thanks for this helpful (😉) package!

The default describe-key gives information of the underlying key under self-insert-command:

+ 'PLUS SIGN' (translated from <kp-add>) runs the command
self-insert-command (found in global-map), which is an interactive
primitive-function in ‘C source code’.

(self-insert-command N &optional C)

Insert the character you type.

Whereas helpful-key doesn't display the underlying key:

self-insert-command is an interactive function defined in cmds.c.

Signature
(self-insert-command N &optional C)

Documentation
Insert the character you type.

Also, if the character doesn't have any action in the current buffer, the helpful-key is not really helpful:

undefined is an interactive and byte-compiled function defined in
subr.el.

Signature
(undefined)