fix typo of point parse

src/Avalonia.Visuals/Point.cs

@@ -175,7 +175,7 @@ namespace Avalonia
         /// Parses a <see cref="Point"/> string.
         /// </summary>
         /// <param name="s">The string.</param>
-        /// <returns>The <see cref="Thickness"/>.</returns>
+        /// <returns>The <see cref="Point"/>.</returns>
         public static Point Parse(string s)
         {
             using (var tokenizer = new StringTokenizer(s, CultureInfo.InvariantCulture, exceptionMessage: "Invalid Point."))