Merge pull request #4267 from MihaZupan/uri-threadsafety

Document that System.Uri is thread-safe

Author: MihaZupan

xml/System/Uri.xml

@@ -233,6 +233,7 @@ Uri baseUri = new Uri(@"\\host\share\some\directory\name\");
   
  ]]></format>
     </remarks>
+    <threadsafe>All members of <see cref="T:System.Uri" /> are thread-safe and may be used concurrently from multiple threads.</threadsafe>
     <altmember cref="T:System.Configuration.IdnElement" />
     <altmember cref="T:System.Configuration.IriParsingElement" />
     <altmember cref="T:System.Configuration.UriSection" />