Generate all Derived implementations in codegen

[nox]

Follow-up of #7873.

@Ms2ger r? :)

[nox]

@bors-servo p=1

[Ms2ger]

-S-awaiting-review +S-needs-code-changes

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Reviewed 93 of 93 files at r1, 78 of 78 files at r2.
Review status: all files reviewed at latest revision, 2 unresolved discussions, all commit checks successful.

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^{components/script/dom/element.rs, line 122 [r2] (raw file):}
This would probably need allow(unrooted_must_root) if that lint worked.

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^{components/script/dom/htmlelement.rs, line 55 [r2] (raw file):}
Or whitelist it in unrooted_must_root.rs if there's a lot of those.

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Comments from the review on Reviewable.io

[nox]

@Ms2ger Whitelisted all new_* functions.

[Ms2ger]

-S-awaiting-review +S-awaiting-merge
@bors-servo r+

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Reviewed 1 of 1 files at r3.
Review status: all files reviewed at latest revision, 2 unresolved discussions, some commit checks pending.

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Comments from the review on Reviewable.io

[bors-servo]

📌 Commit 7d6ea83 has been approved by Ms2ger

[bors-servo]

⌛ Testing commit 7d6ea83 with merge 417cf57...

[bors-servo]

☀️ Test successful - android, gonk, linux-dev, linux-rel, mac-dev-ref-unit, mac-rel-css, mac-rel-wpt