Type aliases without semi-colon break syntax highlighting

[samholmes]

• VSCode Version: 1.50.1
• OS Version: macOS Catalina Version 10.15.6 (19G73)

Steps to Reproduce:

1. Open a .ts file with the following contents:

type Foo = string

(async () => {
	let foo: string

	try {
		foo = "hello"
	} catch (error) {
		// Nothing
	}
})()

Results: Syntax highlighting breaks without a semi-colon inserted. See screenshot:

Syntax highlighting is not broken if we add a semi-colon to the type declaration:

Expected: Syntax highlighting shouldn't break when omitting the semi-colon.

Does this issue occur when all extensions are disabled?: Yes

[sheetalkamat]

This is working as intended because of limitation of textmate grammar rules which doesn't allow lookup beyond line. Duplicate of #352