Ladybird/AppKit: Change "Select All" text to be titlecase

Matches the rest of the menu items and Safari.

Ladybird/AppKit/Application/ApplicationDelegate.mm

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2023-2024, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -351,7 +351,7 @@
                                          keyEquivalent:@"v"]];
     [submenu addItem:[NSMenuItem separatorItem]];
 
-    [submenu addItem:[[NSMenuItem alloc] initWithTitle:@"Select all"
+    [submenu addItem:[[NSMenuItem alloc] initWithTitle:@"Select All"
                                                 action:@selector(selectAll:)
                                          keyEquivalent:@"a"]];