Tweaks to PR details view

- Hide Open/Diff menu for now
- Use correct property for view switching menu item header
- Display changed files count

Author: grokys

src/GitHub.VisualStudio/UI/Views/PullRequestDetailView.xaml

@@ -358,12 +358,12 @@
                 <te:SectionControl Name="changesSection" 
                                    Grid.Column="2" Grid.Row="3"
                                    IsExpanded="True"
-                                   HeaderText="{Binding ChangedFilesCount, StringFormat=Changes ({0})}"
+                                   HeaderText="{Binding ChangedFilesList.Count, StringFormat=Changes ({0})}"
                                    Margin="0 5 10 0"
                                    ContextMenuService.IsEnabled="False">
                     <te:SectionControl.ContextMenu>
                         <ContextMenu>
-                            <MenuItem Command="{Binding ToggleOpenChangedFileAction}">
+                            <MenuItem Command="{Binding ToggleOpenChangedFileAction}" Visibility="Collapsed">
                                 <MenuItem.Style>
                                     <Style TargetType="MenuItem">
                                         <Style.Triggers>
@@ -377,15 +377,15 @@
                                     </Style>
                                 </MenuItem.Style>
                             </MenuItem>
-                            <Separator/>
+                            <Separator Visibility="Collapsed"/>
                             <MenuItem Command="{Binding ToggleChangedFilesView}">
                                 <MenuItem.Style>
                                     <Style TargetType="MenuItem">
                                         <Style.Triggers>
-                                            <DataTrigger Binding="{Binding ChangedFilesView}" Value="TreeView">
+                                            <DataTrigger Binding="{Binding ChangedFilesViewType}" Value="TreeView">
                                                 <Setter Property="Header" Value="Switch to List View"/>
                                             </DataTrigger>
-                                            <DataTrigger Binding="{Binding ChangedFilesView}" Value="ListView">
+                                            <DataTrigger Binding="{Binding ChangedFilesViewType}" Value="ListView">
                                                 <Setter Property="Header" Value="Switch to Tree View"/>
                                             </DataTrigger>
                                         </Style.Triggers>