Prefix operator precedence should be reduced when return value is a lambda which is being applied

```
For example:

    let (~-) x y : System.DateTime = x + y
    <@ (-DateTime.Now) TimeSpan.MinValue @> |> decompile =? "-DateTime.Now TimeSpan.MinValue" //incorrect decomplition: should be (-DateTime.Now) TimeSpan.MinValue
```

Original issue reported on code.google.com by `stephen....@gmail.com` on 13 May 2012 at 3:15
