Support JSON5 for biome.json

[quantizor]

It would be great to be able to put code comments in biome.json to label rules with reasons for settings.

[ematipico]

We decided to refrain from doing so because that would put pressure on other developer tools (mainly editors), to support them too. Especially for comments in a .json file, which isn't valid.

[quantizor]

How about a different file format that supports comments then?

[ematipico]

I think someone proposed biome.jsonc in the Discord server.

I wouldn't mind, but this comes with a price:

• what's the priority between these file extensions? In case we have both of them in the same directory;
• can biome.jsonc extend a biome.json file or vice-versa?

And I would like to have things clarified first.

[GabenGar]

1. No priority, the program should crash if it sees two configs with the same base name but different supported extensions in the same folder and tell the users about it.
2. If they have different base names, why not? The parent config has to be parsed first anyway as per the rule above.

[osdiab]

I consider this relatively important since, using ESLint at my company, if we switched then we'd lose the institutional knowledge for why we configured it that way, disabled certain rules, etc. @GabenGar 's suggestions make total sense to me.

[ematipico]

Closing, track progress in #1259