mark HighPriority as [Obsolete]; more releaes note updates

docs/ReleaseNotes.md

@@ -15,12 +15,14 @@
   the `Subscribe` method has a new overload *without* a handler parameter which returns a `ChannelMessageQueue`, which provides `async` ordered access to messsages)
 - internal: the network architecture has moved to use `System.IO.Pipelines`; this has allowed us to simplify and unify a lot of the network code, and in particular 
   fix a lot of problems relating to how the library worked with TLS and/or .NETStandard
+- change: as a result of the `System.IO.Pipelines` change, the error-reporting on timeouts is now much simpler and clearer; the [timeouts documentation](Timeouts.md) has been updated
+- removed: the `HighPriority` (queue-jumping) flag is now deprecated
 - internal: most buffers internally now make use of pooled memory; `RedisValue` no longer pre-emptively allocates buffers
 - added: asynchronous operations now have full support for reporting timeouts
 - added: new APIs now exist to work with pooled memory without allocations - `RedisValue.CreateFrom(MemoryStream)` and `operator` support for `Memory<byte>` and `ReadOnlyMemory<byte>`; and `IDatabase.StringGetLease[Async](...)`, `IDatabase.HashGetLease[Async](...)`, `Lease<byte>.AsStream()`)
 - added: ["streams"](https://redis.io/topics/streams-intro) support (thanks to [ttingen](https://github.com/ttingen) for their contribution)
 - various missing commands / overloads have been added
-- a *lot* of general bugs and issues have been resolved
+- fix: a *lot* of general bugs and issues have been resolved
 
 a more complete list of issues addressed can be seen in [this tracking issue](https://github.com/StackExchange/StackExchange.Redis/issues/871)
 

src/StackExchange.Redis/Enums/CommandFlags.cs

@@ -12,10 +12,11 @@ public enum CommandFlags
         /// Default behaviour.
         /// </summary>
         None = 0,
+
         /// <summary>
         /// From 2.0, this flag is not used
         /// </summary>
-        // [Obsolete("From 2.0, this flag is not used", false)]
+        [Obsolete("From 2.0, this flag is not used", false)]
         HighPriority = 1,
         /// <summary>
         /// The caller is not interested in the result; the caller will immediately receive a default-value

tests/StackExchange.Redis.Tests/TransactionWrapperTests.cs

@@ -75,15 +75,15 @@ public void AddCondition_StringNotEqual()
         [Fact]
         public void ExecuteAsync()
         {
-            wrapper.ExecuteAsync(CommandFlags.HighPriority);
-            mock.Verify(_ => _.ExecuteAsync(CommandFlags.HighPriority), Times.Once());
+            wrapper.ExecuteAsync(CommandFlags.None);
+            mock.Verify(_ => _.ExecuteAsync(CommandFlags.None), Times.Once());
         }
 
         [Fact]
         public void Execute()
         {
-            wrapper.Execute(CommandFlags.HighPriority);
-            mock.Verify(_ => _.Execute(CommandFlags.HighPriority), Times.Once());
+            wrapper.Execute(CommandFlags.None);
+            mock.Verify(_ => _.Execute(CommandFlags.None), Times.Once());
         }
     }
 #pragma warning restore RCS1047 // Non-asynchronous method name should not end with 'Async'.