fix spelling

index.html

@@ -65,7 +65,7 @@ <h3>Keywords</h3>
             <li><span class="code">require</span>: A condition to prove with formal verification at compile-time.</li>
             <li><span class="code">assume</span>: A condition assumed to be true at compile-time.</li>
             <li><span class="code">sizeof</span>: <a href="https://en.wikipedia.org/wiki/Sizeof">C's <span class="code">sizeof</span></a>.</li>
-            <li><span class="code">unreachable</span>: Denoates the end of execution, all following statements are unreachable.</li>
+            <li><span class="code">unreachable</span>: Marks the end of execution, all following statements are unreachable.</li>
         </ol>
         <h3>Tentative keywords</h3>
         <ol>