Add instruction to use var for declaring variables

[jinolacson]

javascript-4-callbacks/practice.js

Lines 1 to 21 in d3025f7

	/*
	Once you complete a problem, refresh ./SpecRunner.html in your browser and check to see if the problem's test(s) are passing.
	Passed tests will be indicated by a green circle.
	Failed tests will be indicated by a red X.
	You can refresh the page at any time to re-run all the tests.
	In this repo your job is to write functions to make each function call work properly.
	Here's an example of code that will be given to you:
	sayHi('Hi Katie', function(thingToSay){
	alert(thingToSay);
	});
	It would be your job to create the sayHi function:
	var sayHi = function(str, cb){
	cb(str);
	}
	*/

Change into:

/*
  Note: use var for declaring variables

  Once you complete a problem, refresh ./SpecRunner.html in your browser and check to see if the problem's test(s) are passing.
  Passed tests will be indicated by a green circle.
  Failed tests will be indicated by a red X.

  You can refresh the page at any time to re-run all the tests.

  In this repo your job is to write functions to make each function call work properly.

  Here's an example of code that will be given to you:

  sayHi('Hi Katie', function(thingToSay){
    alert(thingToSay);
  });

  It would be your job to create the sayHi function:

  var sayHi = function(str, cb){
    cb(str);
  }
*/