add license header to code files

[UtkarshBhardwaj007]

• This is in continuation to this PR: create a rust workspace for code snippets and migrate 'build-a-custom-pallet' to it #287. Refer there for more context.
• In particular, the code files in the previous PR didn't have license headers. This PR adds license headers to the code files. The repository has license information which was used to determine the license to be used. We are using the MIT-0 License. This is ideal as MIT-0 is a variant of the MIT license that removes the attribution requirement, meaning users can use, copy, modify, and distribute the software without needing to include the original copyright notice and permission notice. Since this repository hosts the code used in tutorials, it is meant to be used/distributed by the users of the repository. Hence MIT-0 seems to be a good fit.
• All code references in the .md files have been updated to +20 to accomodate for the extra lines used by the license header.
• Testing: Tested by building locally, running tests and by serving the doc using mkdocs serve. For snippets, refer here
• Part of Test code snippets #236

[kianenigma]

MIT-0 sounds good to me, requesting @albertov19 to also approve from the papermoon side please :)

[albertov19]

@kianenigma @UtkarshBhardwaj007 The repo has a Creative Commons Attribution 4.0 International license. I'm not a legal expert or anything, but I have a couple of comments:

1. If we are going to have different license sets, we need to ensure they are compatible
2. I would like to see the Copyright (C) 2025 Parity Technologies (UK) Ltd. removed from the files if possible as this is not the case for the content living in this repo (we can discuss if you guys need this to appear in content that you guys solely contribute to)

Let me know your thoughts

[UtkarshBhardwaj007]

1. If we are going to have different license sets, we need to ensure they are compatible

1. From what I understand, the documentation in the repo has a Creative Commons Attribution 4.0 International license but the code in the repo has the MIT License. We are using the MIT-0 license which aligns with the repository documentation unless I am missing something.

2. I believe @kianenigma would be able to answer here. Also @albertov19, what then should the copyright say? Or should we not have any copyright information there at all?

[albertov19]

1. If we are going to have different license sets, we need to ensure they are compatible

1. From what I understand, the documentation in the repo has a Creative Commons Attribution 4.0 International license but the code in the repo has the MIT License. We are using the MIT-0 license which aligns with the repository documentation unless I am missing something.

I remember now that this was the decision made some time ago. MIT is more permissive than CC BY 4.0, the main difference being that CC BY 4.0 requires attribution to the original creator.

Broadly speaking, these licenses are compatible.

I recommend removing the copyright notice in the code snippets and leaving the license there. Wdyt @kianenigma

[UtkarshBhardwaj007]

I recommend removing the copyright notice in the code snippets and leaving the license there.

Done.

[kianenigma]

SGTM, Agree that:

1. No parity mention need to be there
2. The license should be as permissive as possible

[albertov19]

Looks good. I'll let @0xLucca give the final approval

[0xLucca]

LGTM!