feature: Comma-first JSON

[juliancoffee]

Did you check the docs?

• I have read all the lazy.nvim docs

Is your feature request related to a problem? Please describe.

Ok, so lazylock.json is very nice, but it doesn't diff well. Because JSON doesn't allow trailing commas, each new plugin adds a comma to the previous line and adds its own line, so you have two lines changed.
Which is fine, but not perfect.
If you store your lazylock.json in git with dotfiles, it'll produce confusing diffs.

Describe the solution you'd like

{ "blink.cmp": { "branch": "main", "commit": "cb5e346d9e0efa7a3eee7fd4da0b690c48d2a98e" }
, "catppuccin": { "branch": "main", "commit": "5b5e3aef9ad7af84f463d17b5479f06b87d5c429" }
, "conform.nvim": { "branch": "master", "commit": "eebc724d12c5579d733d1f801386e0ceb909d001" }
, "fidget.nvim": { "branch": "main", "commit": "d9ba6b7bfe29b3119a610892af67602641da778e" }
, "lazy.nvim": { "branch": "main", "commit": "6c3bda4aca61a13a9c63f1c1d1b16b9d3be90d7a" }
}

Provide the option to use comma-first.
Looking at my example, I guess I might have overestimated (and underestimated) the problem a bit because lazylock is always sorted alphabetically, so that might be an option to tweak as well.

Describe alternatives you've considered

Just living with it as it is, I guess

Additional context

No response