Update language data and generated files

Author: ptr727

Data/language-subtag-registry

@@ -1,4 +1,4 @@
-File-Date: 2025-05-15
+File-Date: 2025-06-23
 %%
 Type: language
 Subtag: aa
@@ -48555,6 +48555,12 @@ Comments: The subtag represents the old orthography of the Latvian
   language used during c. 1600s–1920s.
 %%
 Type: variant
+Subtag: viennese
+Description: The Viennese dialect of German
+Added: 2025-06-22
+Prefix: de
+%%
+Type: variant
 Subtag: vivaraup
 Description: Vivaro-Alpine
 Added: 2018-04-22

Utilities/Rfc5646Gen.cs

@@ -9,7 +9,7 @@ public bool Create()
         RecordList.Clear();
         Record record;
 
-        FileDate = DateFromString("2025-05-15");
+        FileDate = DateFromString("2025-06-23");
 
         record = new()
         {
@@ -167994,6 +167994,26 @@ public bool Create()
 
         RecordList.Add(record);
 
+        record = new()
+        {
+            Type = RecordType.Variant,
+            SubTag = "viennese",
+            Added = DateFromString("2025-06-22"),
+            SuppressScript = "",
+            Scope = "",
+            MacroLanguage = "",
+            Deprecated = DateFromString("0001-01-01"),
+            PreferredValue = "",
+            Tag = "",
+        };
+
+        // The Viennese dialect of German
+        record.Description.Add(FromEncodedString("VGhlIFZpZW5uZXNlIGRpYWxlY3Qgb2YgR2VybWFu"));
+
+        record.Prefix.Add("de");
+
+        RecordList.Add(record);
+
         record = new()
         {
             Type = RecordType.Variant,