UnixDomainSocketEndPoint constructor exceptions (#3990)

Author: carlossanlop

xml/System.Net.Sockets/UnixDomainSocketEndPoint.xml

@@ -49,6 +49,11 @@
         <param name="path">The path to connect a unix domain socket over.</param>
         <summary>Initializes a new instance of the <see cref="T:System.Net.Sockets.UnixDomainSocketEndPoint" /> with the file path to connect a unix domain socket over.</summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.ArgumentOutOfRangeException">
+          <paramref name="path" /> is of an invalid length for use with domain sockets on this platform. The length must be between 1 and the allowed native path length.</exception>
+        <exception cref="T:System.PlatformNotSupportedException">The current OS does not support Unix Domain Sockets.</exception>
       </Docs>
     </Member>
   </Members>