Custom Media Queries - Add BCD

[ramiy]

I added the CSS @custom-media at-rule in #3325 . But since no browser implemented this feature, we didn't added compat_features param.

Now, Firefox 147 became the first browser to support this feature https://bugzilla.mozilla.org/show_bug.cgi?id=1744292

I updated the BCD project to reflect this change mdn/browser-compat-data#28438

This PR updates the custom-media-queries web feature setting the compat_features param.

[ddbeck]

I think you need to do a bit of explaining here. What happened with the other keys? 😅

[ramiy]

Ok, I added only css.at-rules.custom-media to BCD, the other keys don't exist - no browser supports them.

See BCD v7.1.21 changelog: https://github.com/mdn/browser-compat-data/releases/tag/v7.1.21

You can also check the code: https://github.com/mdn/browser-compat-data/tree/v7.1.21/api

Currently, the CSSCustomMediaRule doesn't exist. Only the CSS @custom-media at-rule is supported.

[ddbeck]

I understood that the key css.at-rules.custom-media was added to BCD mdn/browser-compat-data#28438. But in this PR, you removed the comment for the other keys without explanation.

I went ahead and dug into this myself. I turned on the preference shown in the data and the CSSCustomMediaRule interface is exposed (there's also code for it in the diff from the Firefox bug you linked in BCD). So two things need to happen here:

1. Against BCD, file an issue noting the missing keys or submit a PR to add the data for the missing API yourself.
2. In this PR, reinstate the comment for the api.CSSCustomMediaRule key and its descendants.

[ramiy]

BCD PR: mdn/browser-compat-data#28450