Remove some duplicate periods

src/Avalonia.Base/AvaloniaObjectExtensions.cs

@@ -334,7 +334,7 @@ namespace Avalonia
         /// <typeparamref name="TTarget"/>.
         /// </summary>
         /// <typeparam name="TTarget">The type of the property change sender.</typeparam>
-        /// /// <typeparam name="TValue">The type of the property..</typeparam>
+        /// /// <typeparam name="TValue">The type of the property.</typeparam>
         /// <param name="observable">The property changed observable.</param>
         /// <param name="action">
         /// The method to call. The parameters are the sender and the event args.

src/Avalonia.Base/Platform/IPlatformRenderInterface.cs

@@ -18,7 +18,7 @@ namespace Avalonia.Platform
         /// Creates an ellipse geometry implementation.
         /// </summary>
         /// <param name="rect">The bounds of the ellipse.</param>
-        /// <returns>An ellipse geometry..</returns>
+        /// <returns>An ellipse geometry.</returns>
         IGeometryImpl CreateEllipseGeometry(Rect rect);
 
         /// <summary>

src/Avalonia.Base/Utilities/TypeUtilities.cs

@@ -306,7 +306,7 @@ namespace Avalonia.Utilities
         /// if the value could not be converted.
         /// </summary>
         /// <param name="value">The value to convert.</param>
-        /// <param name="type">The type to convert to..</param>
+        /// <param name="type">The type to convert to.</param>
         /// <param name="culture">The culture to use.</param>
         /// <returns>A value of <paramref name="type"/>.</returns>
         [RequiresUnreferencedCode(TrimmingMessages.TypeConversionRequiresUnreferencedCodeMessage)]