* fix(challenges): Add function scope of use strict
Refactored first 13 challenges with function scope `"use strict";`
syntax
Closes#16254
fix(challenges): Refactor ES6 challenges
Refactored ES6 challenges up to 22 to use function scope `"use strict";`
test(challenges): QA ES6 Challenges
Refactored es6 challenges getting tested and QA'd
fix(challenges): QA remaining ES6 challenges
* refactor(challenges): Quick edit for ES6 challenges
More changes to come. This commit solves issues addressed by Quincy
* refactor(challenges): ES6 Textual refactor
Textual refactor. Improved challenge test messages to be more
explanatory