Method warn

perro_source/devtools/perro_cli/src/doctor.rs:44–48

(&mut self, msg: String)

impl ValidationReport {
    fn warn(&mut self, msg: String) {
        self.warnings += 1;
        self.messages
            .push(format!("{COLOR_YELLOW}[WARN]{COLOR_RESET} {msg}"));
    }

    fn error(&mut self, msg: String) {
        self.errors += 1;