Macro editor should disallow nesting

[MaximilianLloyd]

Here, you have the possibility to add macros. But it breaks the build.

Run for reference: https://github.com/MaximilianLloyd/Adv360-Pro-ZMK/actions/runs/5084127947/jobs/9136019710

[KinesisCorporation]

Noted with thanks!

[KinesisCorporation]

This is now fixed.