Add -vv option for listing supported features #800

Job	Run time
Build tarball distribution	24s
Build HTML document	2m 1s
Build PDF document	1m 48s
Build form on ubuntu-24.04-arm	51s
Build tform on ubuntu-24.04-arm	47s
Build tform on macos-14	1m 4s
Build form on macos-15-intel	2m 28s
Build form on windows-2022	2m 56s
Build tform on ubuntu-24.04	54s
Build tform on macos-15-intel	1m 18s
Build form on ubuntu-24.04	1m 4s
Build form on macos-14	59s
Build tform on windows-2022	20m 26s
Publish binaries to GitHub Releases	1m 20s
	38m 20s

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