Macro loggy::todox

macro_rules! todox {
    (target: $target:expr, $($arg:tt)*) => { ... };
    ($($arg:tt)*) => { ... };
}

Generate a debug log message.

This is identical to invoking debug!(...). Renaming it todox! ensures all uses will be reported by cargo todox, to ensure their removal once their usefulness is past.

Level::Debug messages are given special treatment by loggy. They are always emitted in tests generated by the test_loggy! macro. They are always directed to the standard error stream, and not captured in the log buffer, even in such tests.