Merge pull request #13315 from erictleung/fix/use-em-dash-in-oop

Correct em dash in OOP challenge plus formatting

seed/challenges/02-javascript-algorithms-and-data-structures/object-oriented-programming.json

@@ -724,11 +724,11 @@
       "title": "Set the Child's Prototype to an Instance of the Parent",
       "description": [
         "In the previous challenge you saw the first step for inheriting behavior from the <code>supertype</code> (or parent) <code>Animal</code>: making a new instance of <code>Animal</code>.",
-        "This challenge covers the next step: set the <code>prototype</code> of the <code>subtype</code> (or child) -- in this case, <code>Bird</code> -- to be an instance of <code>Animal</code>.",
+        "This challenge covers the next step: set the <code>prototype</code> of the <code>subtype</code> (or child)&mdash;in this case, <code>Bird</code>&mdash;to be an instance of <code>Animal</code>.",
         "<blockquote>Bird.prototype = Object.create(Animal.prototype);</blockquote>",
         "Remember that the <code>prototype</code> is like the \"recipe\" for creating an object. In a way, the recipe for <code>Bird</code> now includes all the key \"ingredients\" from <code>Animal</code>.",
         "<blockquote>let duck = new Bird(\"Donald\");<br>duck.eat(); // prints \"nom nom nom\"</blockquote>",
-        "<code>duck</code> inherits all of <code>Animal's</code> properties, including the <code>eat</code> method.",
+        "<code>duck</code> inherits all of <code>Animal</code>'s properties, including the <code>eat</code> method.",
         "<hr>",
         "Modify the code so that instances of <code>Dog</code> inherit from <code>Animal</code>."
       ],