Change mod in the layer using unmod action.

[aljustiet]

I have this alias in my alt layer: C-c (unmod C-c). And I want to unmod the alt and press CTRL+c. But I can't do that because I'm having this error when trying to live reload the config:

    ╭─[/home/aljustiet/.config/kanata/config.kbd:355:1]
355 │   C-m (multi (release-key alt) C-m)
356 │   C-c (unmod C-c)
    ·              ─┬─
    ·               ╰── Error here
357 │   C-v (multi (release-key alt) C-v)
    ╰────
 help: unmod expects expects at least one key name
       
       For more info, see the configuration guide:
       https://github.com/jtroo/kanata/blob/main/docs/config.adoc

I don't want to use the release-key action because it releases the key permanently, and the unmod action suits my needs, but it can't somehow activate the chords.

[jtroo]

Please see: #1184