Siblings of quoted arguments aren't scanned for quoted arguments

[Tarmil]

For example, given the following:

type X() =
    member this.Foo([<JavaScript>] e: Expr<_>) = this
    member this.Bar([<JavaScript>] e: Expr<_>) = this

X().Foo(<@ q1 @>).Bar(<@ q2 @>)

The scanner first hits the Bar call, stores its argument in the metadata, but then doesn't recurse on the this of the call and therefore never reaches the Foo call.