Add test cases for void elements with trailing whitespace

Expanded the test suite to include void HTML elements (hr, input, br, img) with trailing whitespace to verify they are converted to self-closing tags. Also updated test case numbering for clarity.

Author: coliff

test/autofix/empty-tag-not-self-closed-test.html

@@ -46,16 +46,22 @@
     <!-- Test case 13: wbr tag (should be converted to self-closing) -->
     <wbr>
 
-    <!-- Test case 14: Already self-closing tags - should not trigger -->
+    <!-- Test case 14: Void elements with trailing whitespace (should be converted to self-closing) -->
+    <hr >
+    <input type="text" >
+    <br   >
+    <img src="test3.jpg" alt="Test 3"  >
+
+    <!-- Test case 15: Already self-closing tags - should not trigger -->
     <br />
     <img src="test2.jpg" alt="Test 2" />
     <hr />
 
-    <!-- Test case 15: Non-void elements with content - should not trigger -->
+    <!-- Test case 16: Non-void elements with content - should not trigger -->
     <div>Content</div>
     <p>Paragraph content</p>
 
-    <!-- Test case 16: Empty non-void elements - should not trigger -->
+    <!-- Test case 17: Empty non-void elements - should not trigger -->
     <div></div>
     <p></p>
   </body>