Update @mdn/browser-compat-data and keep-alive WebTransportWriter

[jakebailey]

WebTransportWriter is apparently missing info.

[saschanaz]

Where is WebTransportWriter from? I don't see any implementation?

[jakebailey]

https://w3c.github.io/webtransport/#webtransportwriter is where this seems to be from

[Bashamega]

w3c.github.io/webtransport#webtransportwriter is where this seems to be from

But there is no actual implementation in the browser
check:
https://source.chromium.org/search?q=WebTransportWriter&sq=
https://searchfox.org/firefox-main/search?q=WebTransportWriter&path=&case=false&regexp=false

[jakebailey]

I've got no idea, if this PR is wrong that's fine, I was just trying to do dep updates here (unrelated to the actual generated code) and hit the same thing that's blocking the automatic updater.

[saschanaz]

I think the WT spec upgraded an existing method or property to use a new sub-interface, we should probably override that.