docs: Added AllowInternals to the usage example

Author: SolidAlloy

Samples~/Usage Examples.meta

@@ -0,0 +1,27 @@
+namespace TypeReferences.Demo.TypeOptions_Examples
+{
+    using System;
+    using UnityEngine;
+    using Utils;
+
+    public class AllowInternal : TypeReferenceExample
+    {
+        [InfoBox("AllowInternal makes internal types appear in the drop-down. By default only public types are shown.")]
+        [Inherits(typeof(IGreetingLogger), AllowInternal = true)]
+        public TypeReference GreetingLoggerType;
+
+        [Button]
+        public void LogGreeting()
+        {
+            if (GreetingLoggerType.Type == null)
+            {
+                Debug.LogWarning("No greeting logger was specified.");
+            }
+            else
+            {
+                var greetingLogger = Activator.CreateInstance(GreetingLoggerType) as IGreetingLogger;
+                greetingLogger.LogGreeting();
+            }
+        }
+    }
+}

Samples~/Usage Examples/Demo.unity

@@ -23,6 +23,14 @@ public void LogGreeting()
         }
     }
 
+    internal class InternalGreetingLogger : IGreetingLogger
+    {
+        public void LogGreeting()
+        {
+            Debug.Log("I am internal.");
+        }
+    }
+
     public abstract class AbstractGreetingLogger : IGreetingLogger
     {
         public abstract void LogGreeting();