style<TextEdit>: using Microsoft YaHei UI for placeholder in TextEdit

src/Views/Controls/TextEdit.cs

@@ -49,7 +49,7 @@ namespace SourceGit.Views.Controls {
                     Placeholder,
                     CultureInfo.CurrentCulture,
                     FlowDirection.LeftToRight,
-                    new Typeface(FontFamily, FontStyle, FontWeight, FontStretch),
+                    new Typeface(new FontFamily("Microsoft YaHei UI"), FontStyle, FontWeight, FontStretch),
                     FontSize,
                     FindResource("Brush.FG2") as Brush,
                     new NumberSubstitution(),

src/Views/Popups/Init.xaml

@@ -38,6 +38,7 @@
         <TextBlock 
             Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2" 
             Text="{DynamicResource Text.Init.Tip}" 
+            FontFamily="Microsoft YaHei UI"
             Foreground="{DynamicResource Brush.FG2}"/>
     </Grid>
 </controls:PopupWidget>