Fix segmentation fault

This segfault occurs in the future commits, but because it's more
important, I'm commiting it first.

src/main.rs

@@ -315,7 +315,7 @@ enum Token {
 impl std::fmt::Display for Token {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		return match self {
-			token @ Token::IntegerLiteral(_) => write!(f, "{}", token),
+			Token::IntegerLiteral(s) => write!(f, "{}", s),
 			token => write!(f, "{}", match token {
 				Token::Plus => "+",
 				Token::Semicolon => ";",