QuickInfo doesn't truncate members on Async<'T> when code is invalid

[cartermp]

Using latest master, in any function, type the following invalid code:

let foo = Async<int>

Then hover over Async.

Expected: A typical Async hover with the members truncated, but with the error message at the bottom.

Actual:

I've been trying to reproduce this in a more general case, but so far only Async seems to be the culprit.

Although this is a bit left field, it could be harmful for people first learning the language getting blasted by the IDE for typing stuff incorrectly.

[dungpa]

What do you expect to see?

[cartermp]

Updated

[cartermp]

This was fixed in #2070.