AK: Add formatters for Utf8View and Utf32View

Useful for debugging, especially in templated contexts.

AK/Utf32View.cpp

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/StringBuilder.h>
+#include <AK/Utf32View.h>
+
+namespace AK {
+
+ErrorOr<void> Formatter<Utf32View>::format(FormatBuilder& builder, Utf32View const& string)
+{
+    return builder.builder().try_append(string);
+}
+
+}