uwriteln to stdout

[vi]

How to I print numbers to stdout with uwriteln!?

There should be either some example in README or crate root doc or explicit statement that it is not possible directly.

[vi]

Found ufmt_utils. Although on itself it does not contain the needed piece, I think it should be mentioned in crate docs that other ufmt_* crates exist.

Anyway a hello-world'esque example would be good for README (e.g. using ufmt_stdio).