/// Converts input string to specified format
/// ```
/// use am_parse::{convert, OutputFormat};
/// assert_eq!(convert("1+1".into(), OutputFormat::Latex, vec![]), "1+1");
/// assert_eq!(convert("fx = 1/2".into(), OutputFormat::Latex, vec!["f"]), "f{\\left(x\\right)}=\\frac{1}{2}");
/// ```