[encoding] Add more labels to the replacement encoding (#8)

As a defense-in-depth measure, it would be great to add the labels mentioned in https://www.w3.org/Bugs/Public/show_bug.cgi?id=21057#c16 to the replacement encoding. It's however unclear whether that is web-compatible, as sites might specify these labels and rely on them not being recognized.

Filing this issue so hopefully one day a browser can experiment and figure out if this is doable.

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Reply to this email directly or view it on GitHub:
https://github.com/whatwg/encoding/issues/8