Snippets: suggest names based on labels if they exist

[cartermp]

If I define a type with labels, e.g.

type BST<'T> =
 | Empty
 | Node of value:'T * left:BST<'T> * right:BST<'T>

Then if I use that type with destructuring syntax and I need to assign names to things, I think that the IDE should suggest a name based on the label if it exists.

let rec flip t = 
 match t with
 | Empty -> t
 | Node(value, left, right) -> ...
// ^^ ^^ ^^
// These are each suggested to me by the IDE.

[xperiandri]

Would be extremely nice!