Everywhere: Use URL::about_XXX factory functions

Author: https://github.com/shannonbooth
Commit: 9072a7caef
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3586
Reviewed-by: https://github.com/tcl3 ✅

UI/AppKit/Application/ApplicationDelegate.mm

@@ -180,7 +180,7 @@
         return;
     }
 
-    [self createNewTab:URL::URL("about:version"sv)
+    [self createNewTab:URL::URL(URL::about_version())
                fromTab:(Tab*)current_tab
            activateTab:Web::HTML::ActivateTab::Yes];
 }