Fix minor typo

index.html

@@ -309,7 +309,7 @@ <h3>Adding New Commands and Keybindings</h3>
                         </div>
                         <div class="tab-pane fade" id="higlighter">
                             <h1>Creating a Syntax Highlighter for Ace</h1>
-                            <p>Creating a new syntax highlighter for Ace is extremly simple. You'll need to define two pieces of code: a new mode, and a new set of highlighting rules.</p>
+                            <p>Creating a new syntax highlighter for Ace is extremely simple. You'll need to define two pieces of code: a new mode, and a new set of highlighting rules.</p>
                             <h2 id="where-to-start"><a class="heading_anchor" href="#where-to-start"><i class="headerLinkIcon"></i></a>Where to Start</h2>
                             <p>We recommend using the the <a href="tool/mode_creator.html">Ace Mode Creator</a> when defining your highlighter. This allows you to inspect your code's tokens, as well as providing a live preview of the syntax highlighter in action.</p>
                             <h2 id="defining-a-mode"><a class="heading_anchor" href="#defining-a-mode"><i class="headerLinkIcon"></i></a>Defining a Mode</h2>