React v17 JSX Transform

[kitsonk]

React introduces a new JSX transform that is supported in TypeScript 4.1: https://devblogs.microsoft.com/typescript/announcing-typescript-4-1-beta/#jsx-factories

We should consider the impact of this on Deno and specifically --no-check.

[kitsonk]

Ref: swc-project/swc#1103

[lucacasonato]

Duplicate of #8440 (closing this because the other issue is more active).

[kitsonk]

🤦