LibWeb: Make HTMLInputElement move cursor into text node when focused

This mechanism feels rather awkward, but it's better than nothing.

Userland/Libraries/LibWeb/HTML/HTMLInputElement.h

@@ -36,6 +36,8 @@ public:
 
     void did_click_button(Badge<Layout::ButtonBox>);
 
+    virtual bool is_focusable() const override;
+
 private:
     // ^DOM::Node
     virtual void inserted() override;
@@ -44,6 +46,9 @@ private:
     // ^HTML::FormAssociatedElement
     virtual HTMLElement& form_associated_element_to_html_element() override { return *this; }
 
+    // ^DOM::EventTarget
+    virtual void did_receive_focus() override;
+
     void create_shadow_tree_if_needed();
 
     RefPtr<DOM::Text> m_text_node;