Use user language instead of system

Localization/LocalizationMod.cs

@@ -160,7 +160,7 @@ namespace Localization
 
         private void TryLoadSystemLanguage()
         {
-            string lang = CultureInfo.InstalledUICulture.EnglishName.Split(' ')[0].ToLower();
+            string lang = CultureInfo.CurrentUICulture.EnglishName.Split(' ')[0].ToLower();
             string first2 = lang.Substring(0, 2);
             // try some possibly valid language codes
             if (File.Exists(Path.Combine(_pluginFolder.FullName, lang + ".json")))