Function emit 

pub fn emit<'a>(
    dest: &mut dyn WriteColor,
    world: &dyn DiagnosticWorld,
    diagnostics: impl IntoIterator<Item = &'a SourceDiagnostic>,
    format: DiagnosticFormat,
) -> Result<(), Error>

Available on crate feature emit-diagnostics only.

Emits diagnostic messages to a writable, colorized output.