Clarify Intptr use in SID constructor (#8969)

Co-authored-by: Adam Sitnik <[email protected]>

Author: henke37

xml/System.Security.Principal/SecurityIdentifier.xml

@@ -81,8 +81,8 @@
         <Parameter Name="binaryForm" Type="System.IntPtr" />
       </Parameters>
       <Docs>
-        <param name="binaryForm">An integer that represents the binary form of a SID.</param>
-        <summary>Initializes a new instance of the <see cref="T:System.Security.Principal.SecurityIdentifier" /> class by using an integer that represents the binary form of a security identifier (SID).</summary>
+        <param name="binaryForm">A pointer to the binary form of a SID.</param>
+        <summary>Initializes a new instance of the <see cref="T:System.Security.Principal.SecurityIdentifier" /> class by using a pointer to the binary form of a security identifier (SID).</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>