Println-debugging alloc and core > format! - instruction incomplete

Thank you for this guide (and, of course, for core, alloc, std).

std-dev-guide.rust-lang.org/development/building-and-debugging.html#println-debugging-alloc-and-core suggests to use format!. But format is not available under core (at least not as std::format!, nor as core::format! - and I thought that format! generates String, which, of course, requires alloc, so format! can't be under core).

Would it work as alloc::format! with #[uses_alloc] or (whatever that is), or how?

If all that people need to debug are tests, or alloc/core functionality invoked from tests, how about mentioning something like the following (if it works):

/// inside (the body of) a non-test core or alloc function:
#[cfg(test)]
{
    use std::format;
    ...
}

Or, could we mention 3rd party #[no_std] (limited) heap-less formatting crates (there is at least one).

Start with the Println-debugging alloc and core section of building-and-debugging.html and verify the available formatting macros in core, alloc, and test contexts. Update the guidance so the example is accurate for core and alloc debugging, including any necessary cfg(test) usage; done means the instructions no longer suggest an unavailable format! path.