WebTransport deprecates out/ingoingHighWaterMark properties

[Elchi3]

Summary

The WebTransport spec renamed two properties:

• s/outgoingHighWaterMark/outgoingMaxBufferedDatagrams/ (and make it ulong) w3c/webtransport#737
• s/incomingHighWaterMark/incomingMaxBufferedDatagrams/ (and make it ulong) w3c/webtransport#735

Test results and supporting details

Firefox ships the change in 152: https://bugzilla.mozilla.org/show_bug.cgi?id=2032789. Firefox doesn't ship this yet.
Chrome doesn't ship it yet: https://issues.chromium.org/issues/494380213
Safari doesn't ship it yet: https://bugs.webkit.org/show_bug.cgi?id=310560

Related issues

None.

[github-actions]

Tip: Review these changes grouped by change (recommended for most PRs), or grouped by feature (for large PRs).

[pepelsbey]

As far as I see, it leads to an awkward moment:

incomingMaxBufferedDatagrams supported in Chrome 97

Which is not the case, as no browsers have shipped it yet.

Maybe we should wait until they are shipped and only then rename?

[Elchi3]

Which is not the case, as no browsers have shipped it yet.

Yes, when opening this PR, I first thought that Firefox would already ship this change. There are examples of this structure in BCD, though, I think even if the new names aren't shipping yet

The alternative would be to not rename but mark the feature as non-standard, as the old names are not in the spec anymore.

[Elchi3]

As discussed in the BCD call today, let's just mark these as non-standard and deprecated for now.
See also https://chromestatus.com/feature/5143839699501056.

We'll add the new names separately when they ship.