title: NavigationLink binding issue
body: <p>I'm 100% brand new to not just Swift but development. I've been through a few books and I'm starting to get it, but I'm probably making some dumb mistake.</p>
  
  <p>The problem is I have a list displaying sets of Measurements() and I'm trying to get a NavigationLink so when a touch happens, the EditMeasurementView opens. I'm not sure what I'm doing wrong.</p>
  
  <p>Here is EditMeasurementView:</p>
  
  <pre><code>struct EditMeasurementView: View {
      @Binding var measurements: Measurements
  
      var body: some View {
          Text(/*@START_MENU_TOKEN@*/"Hello, World!"/*@END_MENU_TOKEN@*/)
      }
  }
  
  struct EditMeasurementView_Previews: PreviewProvider {
      static var previews: some View {
        //EditChecklistItemView(checklistItem: .constant(ChecklistItem(name: "Sample item")))
            EditMeasurementView(measurements:  .constant(Measurements()))
      }
  }
  
  </code></pre>
  
  <p>Here is ContentView:</p>
  
  <pre><code>import SwiftUI
  
  struct ContentView: View {
  
      @ObservedObject var measurements = Measurements()
      @State var newMeasurementViewIsVisible = false
  
      var body: some View {
          NavigationView {
              List {
                  ForEach(measurements.items) { MeasurementItem in
                      NavigationLink(destination: EditMeasurementView(measurements: $measurements)) {
                          HStack {
                              Text("\(MeasurementItem.mdate)")
                              Spacer()
                              Text("\(MeasurementItem.weight)" + " lbs")
                          }
                      }
                  }
                  .onDelete(perform: measurements.deleteListItem)
                  .onMove(perform: measurements.moveListItem)
              }
              .navigationBarTitle("Measurements", displayMode: .inline)
              .navigationBarItems(
                  leading: Button(action: { self.newMeasurementViewIsVisible = true
                    }) {
                      HStack {
                        Image(systemName: "plus.circle.fill")
                        Text("New")
                      }
                    },
                    trailing: EditButton()
              )
          }
          .sheet(isPresented: $newMeasurementViewIsVisible) {
              NewMeasurementItemView(measurements: self.measurements)
          }
      }
  } 
  
  
  struct ContentView_Previews: PreviewProvider {
      static var previews: some View {
          ContentView()
      }
  }
  </code></pre>
  
  <p>The error swift is throwing is:</p>
  
  <pre><code>Cannot convert value of type 'ObservedObject&lt;Measurements&gt;.Wrapper' to
  expected argument type 'Binding&lt;Measurements&gt;'" on the NavigationLink
  line in ContentView.
  </code></pre>