Replace X next to Safari with 9.1+

Safari 9.1 (released on March 21, 2016) now supports
document.execCommand(‘copy’) and document.execCommand(‘cut’)

Also tweak css a bit to fix the styling of the new changes

assets/styles/main.css

@@ -221,7 +221,7 @@ code {
 .support li {
     display: inline-block;
     text-align: center;
-    margin: 5px 8px 0;
+    margin: 5px 7px 0;
 }
 
 .support p {

index.html

@@ -200,7 +200,7 @@ clipboard.destroy();</code></pre>
             </li>
             <li>
                 <img src="assets/images/safari.png" width="64" height="64" alt="Safari logo">
-                <p>Safari ✘</p>
+                <p>Safari 9.1+</p>
             </li>
         </ul>