Link Exclusive Accordion to web-features id

[foolip]

This is using the same tagging approach as in BCD:
https://github.com/mdn/browser-compat-data/blob/74547d66328d241c6b7d171adc3cdf7bce8872dd/html/elements/dialog.json#L9

[foolip]

@SachaG would you prefer a new webFeatures field?

[SachaG]

I think maybe it should be its own separate field? It's a bit weird to use the tags field for that?

[SachaG]

@SachaG would you prefer a new webFeatures field?

Yes that would make more sense to me. In fact I think ideally we would just use the web feature id as the canonical id field, but that might not be practical for backwards-compatibility reasons.

[SachaG]

Maybe we could name the field something like webFeaturesId, or wfId? web-features by itself doesn't really communicate the fact that it's a canonical ID?

[foolip]

@SachaG webFeaturesId works for me, it's pretty explicit and easy to search for. I'll update this PR to show what it'd look like.

[SachaG]

1 done, 678 to go! (I'm guessing, I didn't count…)