Correct syntax in isProperFraction function

Fix syntax error in isProperFraction function.

Author: Yonatanteklemariam

Sprint-3/1-implement-and-rewrite-tests/implement/2-is-proper-fraction.js

@@ -24,6 +24,7 @@ numerator = Number(numerator);
 denominator = Number(denominator);
 if (isNaN(numerator) || isNaN(denominator) {
 return false;})
+*/
 // The line below allows us to load the isProperFraction function into tests in other files.
 // This will be useful in the "rewrite tests with jest" step.
 module.exports = isProperFraction;