LibWeb: Remove unused Document::fixup()

This was some naive fixup mechanism we used before implementing a spec
compliant HTML parser.

Libraries/LibWeb/DOM/Document.cpp

@@ -108,21 +108,6 @@ bool Document::is_child_allowed(const Node& node) const
     }
 }
 
-void Document::fixup()
-{
-    if (!first_child() || !is<DocumentType>(*first_child()))
-        prepend_child(adopt(*new DocumentType(*this)));
-
-    if (is<HTML::HTMLHtmlElement>(first_child()->next_sibling()))
-        return;
-
-    auto body = create_element("body");
-    auto html = create_element("html");
-    html->append_child(body);
-    this->donate_all_children_to(body);
-    this->append_child(html);
-}
-
 const Element* Document::document_element() const
 {
     return first_child_of_type<Element>();

Libraries/LibWeb/DOM/Document.h

@@ -69,8 +69,6 @@ public:
 
     URL complete_url(const String&) const;
 
-    void fixup();
-
     CSS::StyleResolver& style_resolver() { return *m_style_resolver; }
     const CSS::StyleResolver& style_resolver() const { return *m_style_resolver; }