Mention C# native integers in IntPtr/UIntPtr docs (#7364)

MSDN-WhiteKnight · web-flow · commit b224e41385fc · 2021-11-08T10:26:28.000-05:00
* Update IntPtr.xml

* Update UIntPtr.xml
diff --git a/xml/System/IntPtr.xml b/xml/System/IntPtr.xml
@@ -107,6 +107,8 @@
  The <xref:System.IntPtr> type is CLS-compliant, while the <xref:System.UIntPtr> type is not. Only the <xref:System.IntPtr> type is used in the common language runtime. The <xref:System.UIntPtr> type is provided mostly to maintain architectural symmetry with the <xref:System.IntPtr> type.  
   
  This type implements the <xref:System.Runtime.Serialization.ISerializable>, and, in .NET 5.0 and later, the <xref:System.IFormattable> interfaces.
+ 
+ In C# starting from version 9.0, you can use the built-in `nint` type to define native-sized integers. This type is represented by the <xref:System.IntPtr> type internally and provides operations and conversions that are appropriate for integer types. For more information, see [nint and nuint types](/dotnet/csharp/language-reference/builtin-types/nint-nuint).
   
 ## Examples
 
diff --git a/xml/System/UIntPtr.xml b/xml/System/UIntPtr.xml
@@ -110,6 +110,8 @@
  The <xref:System.UIntPtr> type can be used by languages that support pointers, and as a common means of referring to data between languages that do and do not support pointers. <xref:System.UIntPtr> objects can also be used to hold handles.  
   
  This type implements the <xref:System.Runtime.Serialization.ISerializable>, and, in .NET 5.0 and later, the <xref:System.IFormattable> interfaces.
+ 
+ In C# starting from version 9.0, you can use the built-in `nuint` type to define native-sized integers. This type is represented by the <xref:System.UIntPtr> type internally and provides operations and conversions that are appropriate for integer types. For more information, see [nint and nuint types](/dotnet/csharp/language-reference/builtin-types/nint-nuint).
   
  ]]></format>
     </remarks>
