replace "it's" by "its" (and vice versa) in descriptions and replace 'to lookup' by 'to look up'

challenges/01-responsive-web-design/applied-accessibility.json

@@ -378,7 +378,7 @@
       "title": "Improve Accessibility of Audio Content with the audio Element",
       "description": [
         "HTML5's <code>audio</code> element gives semantic meaning when it wraps sound or audio stream content in your markup. Audio content also needs a text alternative to be accessible to the deaf or hard of hearing. This can be done with nearby text on the page or a link to a transcript.",
-        "The <code>audio</code> tag supports the <code>controls</code> attribute. This shows the browser default play, pause, and other controls, and supports keyboard functionality. This is a boolean attribute, meaning it doesn't need a value, it's presence on the tag turns the setting on.",
+        "The <code>audio</code> tag supports the <code>controls</code> attribute. This shows the browser default play, pause, and other controls, and supports keyboard functionality. This is a boolean attribute, meaning it doesn't need a value, its presence on the tag turns the setting on.",
         "Here's an example:",
         "<blockquote>&lt;audio id=&quot;meowClip&quot; controls&gt;<br>    &lt;source src=&quot;audio/meow.mp3&quot; type=&quot;audio/mpeg&quot; /&gt;<br>    &lt;source src=&quot;audio/meow.ogg&quot; type=&quot;audio/ogg&quot; /&gt;<br>&lt;/audio&gt;<br></blockquote>",
         "<strong>Note</strong><br>Multimedia content usually has both visual and auditory components. It needs synchronized captions and a transcript so users with visual and/or auditory impairments can access it. Generally, a web developer is not responsible for creating the captions or transcript, but needs to know to include them.",