Remove unneeded parentheses enum

src/format.rs

@@ -2,16 +2,3 @@ mod formulas;
 mod terms;
 
 pub(crate) use terms::*;
-
-trait Precedence
-{
-	fn precedence_level(&self) -> i32;
-}
-
-#[derive(Clone, Copy, Eq, PartialEq)]
-pub(crate) enum Parentheses
-{
-	None,
-	PrecedenceBased(i32),
-	Required,
-}