Same shortcut for two different actions

I have set up a shortcut in skhdrc to toggle the `topmost` of sketchybar using two different key combinations:

```
# sketchybar
fn - b : sketchybar --bar topmost=on
fn - m : sketchybar --bar topmost=off
```

Is it possible to toggle the `topmost` with just one combination? If `topmost` is "on", turn it "off", and vice versa?

Start with the skhdrc shortcut entries shown in the issue and inspect skhd's command execution and documentation for how one shortcut can invoke an external command. Check whether the requested state change belongs in skhd or sketchybar, then verify the behavior with a minimal configuration; done means one key combination reliably switches topmost between on and off.

Written by the indexing model from the issue text.