Added the informal address to the BeyondFacts Lab (#1176)

app/MindWork AI Studio/Settings/DataModel/AddressForm.cs

@@ -0,0 +1,22 @@
+namespace AIStudio.Settings.DataModel;
+
+/// <summary>
+/// How a text addresses the person in languages which tell a formal address from an informal one, such as German,
+/// French, or Spanish.
+/// </summary>
+/// <remarks>
+/// Only texts of TA() have both forms; see I18N.AddressForm.
+/// </remarks>
+public enum AddressForm
+{
+    /// <summary>
+    /// The formal address, such as "Sie" in German, "vous" in French, or "usted" in Spanish. All texts of AI Studio
+    /// use it, unless the person chose otherwise.
+    /// </summary>
+    FORMAL,
+
+    /// <summary>
+    /// The informal address, such as "du" in German, "tu" in French, or "tú" in Spanish.
+    /// </summary>
+    INFORMAL,
+}