[Bug, FCS, Tooltips] Parameter name isn't visible in a tooltip when parameter is a tuple

Please provide a succinct description of the issue.

Doesn't work when parameter is a tuple:
``` fsharp
let receivesTuple thisIsAVeryImportantTupleName =
let (a, b) = thisIsAVeryImportantTupleName
a + b
```

But works when parameter is a struct tuple:
``` fsharp
let receivesStructTuple thisIsAVeryImportantTupleName =
let struct (a, b) = thisIsAVeryImportantTupleName
a + b
```

Both in Rider and Visual Studio