Create a rule to add a specific format to file headers

[jesus-mg-ios]

Add a file headers format like swiftformat (the other one does), but we can improve it, by adding a way to insert variables and, using the created date .year not from the file, but from the git.

[ahoppen]

Synced to Apple’s issue tracker as rdar://129247437

[sdavids]

You might want to support the REUSE header format:

https://reuse.software/faq/#why-reuse

// SPDX-FileCopyrightText: 2024 Jane Doe <jane@example.com>
//
// SPDX-License-Identifier: BSD-3-Clause-No-Military-License

/*
 * SPDX-FileCopyrightText: 2020-2024 John Doe <john@example.com>
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 */