Add an underscore to "Use explanatory variables"

This makes the destructuring a little more readable

README.md

@@ -125,7 +125,7 @@ saveCityZipCode(
 ```javascript
 const address = "One Infinite Loop, Cupertino 95014";
 const cityZipCodeRegex = /^[^,\\]+[,\\\s]+(.+?)\s*(\d{5})?$/;
-const [city, zipCode] = address.match(cityZipCodeRegex) || [];
+const [_, city, zipCode] = address.match(cityZipCodeRegex) || [];
 saveCityZipCode(city, zipCode);
 ```