Document System.IO.Pipes.PipeOptions.CurrentUserOnly (#3411)

* Document System.IO.Pipes.PipeOptions.CurrentUserOnly

* suggestion by danmosemsft

* fix typo

Author: carlossanlop

xml/System.IO.Pipes/PipeOptions.xml

@@ -102,7 +102,7 @@
       </ReturnValue>
       <MemberValue>536870912</MemberValue>
       <Docs>
-        <summary>To be added.</summary>
+        <summary>When used to create a <see cref="T:System.IO.Pipes.NamedPipeServerStream" /> instance, indicates that the pipe can only be connected to a client created by the same user. When used to create a <see cref="T:System.IO.Pipes.NamedPipeClientStream" /> instance, indicates that the pipe can only connect to a server created by the same user. On Windows, it verifies both the user account and elevation level.</summary>
       </Docs>
     </Member>
     <Member MemberName="None">