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

app/MindWork AI Studio/Tools/PluginSystem/ILanguagePluginExtensions.cs

@@ -0,0 +1,33 @@
+using SharedTools;
+
+namespace AIStudio.Tools.PluginSystem;
+
+public static class ILanguagePluginExtensions
+{
+    /// <param name="plugin">The language plugin.</param>
+    extension(ILanguagePlugin plugin)
+    {
+        /// <summary>
+        /// Checks whether the language tells a formal address from an informal one, so that a choice between both
+        /// makes sense.
+        /// </summary>
+        /// <remarks>
+        /// The plugin decides by its texts, not by a list of languages: it needs an informal variant of a text of
+        /// TA() which reads differently than the formal one. English addresses everybody alike, so its plugin holds
+        /// the informal variants in the same words. A language translated before it got informal variants offers
+        /// no choice either, since it would change nothing.
+        /// </remarks>
+        /// <returns>True, when at least one informal variant differs from its formal one.</returns>
+        public bool HasInformalAddress()
+        {
+            var content = plugin.Content;
+            foreach (var (key, text) in content)
+            {
+                if (I18NAddressVariant.TryGetFormalKey(key, out var formalKey) && content.TryGetValue(formalKey, out var formalText) && !string.Equals(text, formalText, StringComparison.Ordinal))
+                    return true;
+            }
+
+            return false;
+        }
+    }
+}