test: rephrase test to specify numerator is zero and denominator is non-zero

Author: Eugenie-A

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

@@ -9,8 +9,8 @@ test(`should return false when denominator is zero`, () => {
   expect(isProperFraction(1, 0)).toEqual(false);
 });
 
-// Special case: numerator is zero
-test(`should return true when numerator is zero`, () => {
+// Special case: numerator is zero and denominator is non-zero
+test(`should return true when numerator is zero and denominator is non-zero`, () => {
   expect(isProperFraction(0, 4)).toEqual(true);
 });