ghc-9.8.1 --supported-extensions doesn't report JavaScriptFFI

... but it does report NoJavaScriptFFI:

% ghc-9.8.1 --supported-extensions|grep JavaScriptFFI
NoJavaScriptFFI

... which is very weird.

Also from .cabal perspective, not reporting JavaScriptFFI in --supported-extensions is questionable (as it is accepted). Not reporting the extensions prevents its usage in default-extensions or other-extensions fields.

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