jQuery: Add a self-closed tag back to an example

This adds an actual quick-closed tag in this code example, as it is implied by the text that there can be one:

> Tags that cannot contain elements may be quick-closed or not:
> ```js
> $( "<img>" );
> $( "<input>" );
> ```

to:

> Tags that cannot contain elements may be quick-closed or not:
> ```js
> $( "<img />" );
> $( "<input>" );
> ```

Closes gh-1264

entries/jQuery.xml

@@ -183,7 +183,7 @@ $( myForm.elements ).hide();
       <pre><code>$( "&lt;a href='https://jquery.com'&gt;&lt;/a&gt;" );</code></pre>
       <p>Tags that cannot contain elements may be quick-closed or not:</p>
       <pre><code>
-$( "&lt;img&gt;" );
+$( "&lt;img /&gt;" );
 $( "&lt;input&gt;" );
       </code></pre>
       <p>When passing HTML to <code>jQuery()</code>, note that text nodes are not treated as DOM elements. With the exception of a few methods (such as <code>.content()</code>), they are generally ignored or removed. E.g:</p>