Fix syntax highligiting for generic function

[yuezk]

Test case:

The generic function use case:

const head = <T>(arr: T[]): T => arr[0];

This will break the use case like:

const title = <T>(This is a title element)</T>;

But I think the latter case is less common and we can avoid it by using another component name. While the generic function is a more common use case and the workaround <T,> is a bit of hacky.

#86