Remove implicit `public`

[octref]

In vscode.d.ts, we don't seem to use public.

SemanticTokensLegend is the only one, and it causes our DefinitelyTyped publisher to fail.
https://dev.azure.com/definitelytyped/DefinitelyTyped/_build/results?buildId=40413&view=logs&j=8635df7d-ecde-52a7-c7a8-84b998e35690&t=c264d665-0b79-59b7-7e04-9965cbe74860

I disabled the TSLint rule for now to publish the types, but we should remove the implicit public.