Fix typo

Author: jondy

pyarmor/index.html

@@ -26,7 +26,7 @@ <h5 class="card-title text-center">Learn</h5>
             <div class="card-body">
               <h5 class="card-title text-center">Ask</h5>
               <a href="ask/en/index.html" class="btn btn-light stretched-link w-100">
-                Something is wrong, or something is not ure
+                Something is wrong, or something is not sure
               </a>
             </div>
           </div>