fixed NumOp documentation
@@ -18,6 +18,7 @@ pub trait Operator {
/// Arithmetic operators take numerical values (either literals or variables)
/// as their operands and return a single numerical value.
+///
/// More information:
/// - MDN documentation:
/// <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Expressions_and_Operators#Arithmetic>
