Enforce alphabetical order for supported file types list

[sindresorhus]

I don't want it alphabetical until we have some kind simple script that can enforce it. Otherwise, I'm stuck having to comment about the order on every other pull request.

https://github.com/sindresorhus/file-type#supported-file-types

[votruongan]

I think that you can sort the Supported file types in readme.md once, and write a test to ensure the Supported file types in readme.md is alphabetically ordered. From then on, every PR will have the description line in the readme.md placed appropriately by the author themself. After that, their PR will be checked by the your written test.

Just like how npm enforces alphabetical order: https://github.com/npm/npm-expansions