[enhancement] trace_fmt should support formatting u8[N] as strings

[proppy]

What's hard to do? (limit 100 words)

currently printing a u8[N] w/ trace_fmt and {} result in printing the underlying u8 array, making it challening to display data-driven trace labels in table-based test function.

Current best alternative workaround (limit 100 words)

none that I know of.

Your view of the "best case XLS enhancement" (limit 100 words)

ideally we have a new format directive {:s} that interpret and print the underlying u8[N] as a string