[spec] Update the definition of `tagtype` and its subtyping (#1862) #272

Job	Run time
build-legacy-exceptions-core-spec	2m 13s
build-legacy-exceptions-js-api-spec	27s
build-js-api-spec	26s
build-core-spec	7m 53s
build-spec-versions	4s
build-web-api-spec	29s
build-code-metadata-spec	4m 13s
publish-spec	16s
	16m 1s

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