Set custom icons for macro groups

[thetic]

Requested feature:

When managing macros in "Expert" mode, I would like to assign custom icons to groups instead of showing them all with the same "<>" icon.

Solves the following problem:

Icons already allow quickly identifying built-in sections like "Extruder" and "Machine." Macro groups, however, cannot be quickly identified because they have the same generic icon.

Additional information:

No response