Corrected wrong value of ClientCertificateOptions

xml/System.Net.Http/HttpClientHandler.xml

@@ -281,7 +281,7 @@ After NuGet package v4.3.2, the default value of <xref:System.Net.DecompressionM
       </ReturnValue>
       <Docs>
         <summary>Gets or sets a value that indicates if the certificate is automatically picked from the certificate store or if the caller is allowed to pass in a specific client certificate.</summary>
-        <value>The collection of security certificates associated with this handler.</value>
+        <value>One of the values defined in the <see cref="T:System.Net.Http.ClientCertificateOption" /> enumeration. The default value is Manual.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>