Fix bottom margin for reply textbox

Author: donokuda

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

@@ -166,7 +166,7 @@
                               AcceptsReturn="True"
                               AcceptsTab="True"
                               IsReadOnly="{Binding IsReadOnly}"
-                              Margin="4 0"
+                              Margin="4 0 4 4"
                               Text="{Binding Body, UpdateSourceTrigger=PropertyChanged}"
                               TextWrapping="Wrap"
                               VerticalAlignment="Center"