LibWeb: Add fast_is for span and div

Author: https://github.com/teaalltr 🔰
Commit: a3e485e2d0
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4459
Reviewed-by: https://github.com/AtkinsSJ ✅

Libraries/LibWeb/HTML/HTMLSpanElement.h

@@ -21,6 +21,8 @@ public:
     // https://www.w3.org/TR/html-aria/#el-span
     virtual Optional<ARIA::Role> default_role() const override { return ARIA::Role::generic; }
 
+    virtual bool is_html_span_element() const override { return true; }
+
 private:
     HTMLSpanElement(DOM::Document&, DOM::QualifiedName);
 
@@ -28,3 +30,8 @@ private:
 };
 
 }
+
+namespace Web::DOM {
+template<>
+inline bool Node::fast_is<HTML::HTMLSpanElement>() const { return is_html_span_element(); }
+}