[HtmlSanitizer] fix PHP config examples

Author: xabbuh

html_sanitizer.rst

@@ -370,7 +370,7 @@ attributes from the `W3C Standard Proposal`_ are allowed.
                     ->allowElement('img', 'src')
 
                     // allow the <h1> element with all safe attributes
-                    ->allowElement('h1')
+                    ->allowElement('h1', '*')
             ;
         };
 
@@ -611,8 +611,7 @@ This option allows you to disallow attributes that were allowed before.
             $framework->htmlSanitizer()
                 ->sanitizer('app.post_sanitizer')
                     // allow the "data-attr" on all safe elements...
-                    ->allowAttribute('data-attr')
-                        ->element('*')
+                    ->allowAttribute('data-attr', '*')
 
                     // ...except for the <section> element
                     ->dropAttribute('data-attr', ['section'])
@@ -630,7 +629,7 @@ This option allows you to disallow attributes that were allowed before.
         $postSanitizer = new HtmlSanitizer(
             (new HtmlSanitizerConfig())
                 // allow the "data-attr" on all safe elements...
-                ->allowAttribute('data-attr')
+                ->allowAttribute('data-attr', '*')
 
                 // ...except for the <section> element
                 ->dropAttribute('data-attr', ['section'])