add t Enum EnumItem and enum to t.d.ts

[coveralls]

Pull Request Test Coverage Report for Build 465451221

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 437262678:	0.0%
Covered Lines:	337
Relevant Lines:	337

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💛 - Coveralls