Add support for Import Assertions higlight

[IllusionMH]

TS and JS Grammar Extension version: N/A Sorry, extension link is broken.

Using latest VS Code Insiders version version: 1.63.0-insider (ed3018, 2021-11-23T05:33:39.595Z)
Also search in repo shows assert only as method on console or function.

TS added support for Import Assertions in 4.5 Announcement

Proposed syntax

Code

import json from "./foo.json" assert { type: "json" };

export { val } from './foo.js' assert { type: "javascript" };

In editor assert is not colored as keyword and object-like notation for attributes differs from plain object (my expectation is that they will be similar, at least strings are handled as strings).

One think to consider - Bikeshed possible syntaxes for import statements #6 is still open, however initial syntax already was updates and implementations follow new syntax (shown above)