Add support for flake.lock

[figsoda]

Make flake.lock files JSON and mark them as generated.

Description

flake.lock is the lock file for Nix flakes generated by the nix command.

Checklist:

• I am associating a language with a new file extension
  • The new extension is used in hundreds of repositories on GitHub.com:
    24.7k results for path:**/flake.lock
  • I have included a real-world usage sample:
    • Sample source:
    • Sample license(s):
  • I have included a change to the heuristics
• I am adding new or changing current functionality
  • I have added or updated the tests for the new or changed functionality.

[Alhadis]

Looks great. Real-world distribution checks out. Just to confirm the origin of the sample you've added, this is one that you've created, correct? I saw your username listed in one of the fields, but I'd rather not go off an assumption.

[figsoda]

It is, it is copied from https://github.com/figsoda/cfg/blob/main/flake.lock, probably one commit or so behind main

[figsoda]

The test fail seems to be because that name is the full path of the file, maybe something like !!name.match((^|\/)flake\.lock$) would work?

[Alhadis]

The test fail seems to be because that name is the full path of the file

Shit, you're right. 🤔 So many of these tests are interrogating only the basename(3) of a file path, it didn't occur to me that there might be a dirname(3) component. And, of course, it doesn't help that the property in question has a misleading name/description…

In any case, these oversights are beyond the scope of this PR. For now, we'll just get these tests passing.

[lildude]

LGTM. Thanks.

Note: this PR will not be merged until close to when the next release is made. See here for more details.