fix: set culture info for whole app

XIVChat Desktop/App.xaml.cs

@@ -1,7 +1,9 @@
 using System;
 using System.ComponentModel;
+using System.Globalization;
 using System.Threading.Tasks;
 using System.Windows;
+using System.Windows.Markup;
 
 namespace XIVChat_Desktop {
     /// <summary>
@@ -53,6 +55,13 @@ namespace XIVChat_Desktop {
                 MessageBox.Show($"Could not save configuration file. {ex.Message}");
             }
 
+            FrameworkElement.LanguageProperty.OverrideMetadata(
+                typeof(FrameworkElement),
+                new FrameworkPropertyMetadata(
+                    XmlLanguage.GetLanguage(CultureInfo.CurrentCulture.IetfLanguageTag)
+                )
+            );
+
             var wnd = new MainWindow();
             this.Window = wnd;