refactor: minor cleanup

ir/src/error.rs

@@ -1,11 +1,11 @@
 #[derive(Debug)]
 pub enum SemanticError {
-    InvalidConstraint(String),
-    InvalidIdentifier(String),
     DuplicateIdentifier(String),
-    InvalidUsage(String),
     IndexOutOfRange(String),
-    TooManyConstraints(String),
+    InvalidConstraint(String),
+    InvalidIdentifier(String),
     InvalidPeriodicColumn(String),
+    InvalidUsage(String),
     MissingDeclaration(String),
+    TooManyConstraints(String),
 }

ir/src/symbol_table.rs

@@ -154,6 +154,8 @@ impl SymbolTable {
         Ok(())
     }
 
+    /// Consumes this symbol table and returns the information required for declaring public inputs
+    /// and periodic columns for the AIR.
     pub(super) fn into_declarations(self) -> (PublicInputs, PeriodicColumns) {
         (self.public_inputs, self.periodic_columns)
     }