chore: update doc

Author: ota-meshi

docs/rules/no-trailing-spaces.md

@@ -35,10 +35,14 @@ This rule supports HTML comments generated by [svelte-eslint-parser].
 </script>
 
 <!-- ✓ GOOD -->
-<div />
+<div>
+  Text
+</div>
 
 <!-- ✗ BAD -->
-<div />  
+<div>  
+  Text  
+</div>
 ```
 
 <!-- prettier-ignore-end -->