Fix typos (#15267)

* Correct a priority value in property set log message

* Correct a comment

src/Avalonia.Base/AvaloniaObject.cs

@@ -326,7 +326,7 @@ namespace Avalonia
             VerifyAccess();
             ValidatePriority(priority);
 
-            LogPropertySet(property, value, BindingPriority.LocalValue);
+            LogPropertySet(property, value, priority);
 
             if (value is UnsetValueType)
             {

src/Avalonia.Base/AvaloniaProperty.cs

@@ -271,7 +271,7 @@ namespace Avalonia
         }
 
         /// <summary>
-        /// Registers an attached <see cref="AvaloniaProperty"/>.
+        /// Registers a <see cref="AvaloniaProperty"/>.
         /// </summary>
         /// <typeparam name="TOwner">The type of the class that is registering the property.</typeparam>
         /// <typeparam name="TValue">The type of the property's value.</typeparam>