Adapt project for Astzweig

Sources/Mustache/String.swift

@@ -1,17 +1,3 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Hummingbird server framework project
-//
-// Copyright (c) 2021-2021 the Hummingbird authors
-// Licensed under Apache License v2.0
-//
-// See LICENSE.txt for license information
-// See hummingbird/CONTRIBUTORS.txt for the list of Hummingbird authors
-//
-// SPDX-License-Identifier: Apache-2.0
-//
-//===----------------------------------------------------------------------===//
-
 extension String {
     private static let htmlEscapedCharacters: [Character: String] = [
         "<": "&lt;",