MacPDF: Use Serenity license headers, remove Xcode boilerplate

Meta/Lagom/Contrib/MacPDF/AppDelegate.mm

@@ -1,16 +1,14 @@
-//
-//  AppDelegate.m
-//  SerenityPDF
-//
-//  Created by Nico Weber on 7/22/23.
-//
+/*
+ * Copyright (c) 2023, Nico Weber <thakis@chromium.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
 
 #import "AppDelegate.h"
 
 #include <LibGfx/Font/FontDatabase.h>
 
 @interface AppDelegate ()
-
 @property (strong) IBOutlet NSWindow* window;
 @end
 
@@ -18,7 +16,6 @@
 
 - (void)applicationDidFinishLaunching:(NSNotification*)aNotification
 {
-    // Insert code here to initialize your application
     // FIXME: copy the fonts to the bundle or something
     auto source_root = DeprecatedString("/Users/thakis/src/serenity");
     Gfx::FontDatabase::set_default_fonts_lookup_path(DeprecatedString::formatted("{}/Base/res/fonts", source_root));
@@ -26,7 +23,6 @@
 
 - (void)applicationWillTerminate:(NSNotification*)aNotification
 {
-    // Insert code here to tear down your application
 }
 
 - (BOOL)applicationSupportsSecureRestorableState:(NSApplication*)app