Fix grammar in accessibility.html

Minor grammatical fix

src/accessibility.html

@@ -15,7 +15,7 @@ relative_path: ../
     <div class="row">
       <div class="col-md-6">
         <p class="lead">
-          Icons are symbols that can convey a ton of information and really help people comprehend directions, signs, and interfaces. Its important that we create and use them so that they can reach the largest amount of people possible.
+          Icons are symbols that can convey a ton of information and really help people comprehend directions, signs, and interfaces. It's important that we create and use them so that they can reach the largest amount of people possible.
         </p>
       </div>
       <div class="col-md-6">