Function onigiri::validator::is_symbol

pub fn is_symbol(vc: &Vec<char>) -> bool

Validate Vec<char> whether it is symbol.

let test_vc = vec!['+'];
assert_eq!(
    onigiri::validator::is_symbol(&test_vc),
    true
);
let test_vc_2 = vec!['2'];
assert_eq!(
    onigiri::validator::is_symbol(&test_vc_2),
    false
);
let test_vc_3 = vec!['+', '+'];
assert_eq!(
    onigiri::validator::is_symbol(&test_vc_3),
    false
);