Typo in `FloatBase` and `IntegerBase` enum

[hyunsukimsokcho]

In src/ast.rs

#[derive(Debug, PartialEq, Clone)]
pub enum IntegerBase {
    Decimal,
    Octal,
    Hexademical,
}

// ..

#[derive(Debug, PartialEq, Clone)]
pub enum FloatBase {
    Decimal,
    Hexademical,
}

I think in both enum, Hexademical may be changed to Hexadecimal if the wording is not intended to prevent any confusion.

P.S. I am enjoying using your library where my colleagues and I are building Educational C compiler written in rust.