added AK2001 warning docs

docs/articles/debugging/akka-analyzers.md

@@ -16,3 +16,4 @@ Akka.Analyzer is a [Roslyn Analysis and Code Fix](https://learn.microsoft.com/en
 | [AK1000](xref:AK1000) | Do not use `new` to create actors.                     | Error    | Actor Design |
 | [AK1001](xref:AK1001) | Should always close over `Sender` when using `PipeTo`. | Error    | Actor Design |
 | [AK2000](xref:AK2000) | Do not use `Ask` with `TimeSpan.Zero` for timeout.     | Error    | API Usage    |
+| [AK2001](xref:AK2001) | Do not use automatically handled messages in inside `Akka.Cluster.Sharding.IMessageExtractor`s.     | Warning    | API Usage    |

docs/articles/debugging/rules/AK2001.md

@@ -0,0 +1,61 @@
+---
+uid: AK2001
+title: Akka.Analyzers Rule AK2001 - "Do not use automatically handled messages in inside `Akka.Cluster.Sharding.IMessageExtractor`s."
+---
+
+# AK2000 - Warning
+
+Do not use automatically handled messages in inside [`Akka.Cluster.Sharding.IMessageExtractor`](xref:Akka.Cluster.Sharding.IMessageExtractor)s.
+
+## Cause
+
+As of Akka.NET v1.5.15, [Akka.Cluster.Sharding is guaranteed to automatically handle the following built-in messages](https://github.com/akkadotnet/akka.net/pull/6863):
+
+* [`ShardRegion.StartEntity`](xref:Akka.Cluster.Sharding.ShardRegion.StartEntity) - used whenever [Akka.Cluster.Sharding's `remember-entities` feature](xref:cluster-sharding#remembering-entities) is enabled.
+* [`ShardingEnvelope`](xref:Akka.Cluster.Sharding.ShardingEnvelope) - a generic envelope type that can be used to send arbitrary messages to entity actors.
+
+Whenever a user tries to manually handle either of these messages, they're performing duplicate work - this rule is in effect to spot wasteful situations and to automatically provide a Roslyn code fix to resolve them.
+
+An example:
+
+```csharp
+using Akka.Cluster.Sharding;
+
+public sealed class MessageExtractor : HashCodeMessageExtractor
+{
+    public MessageExtractor() : base(maxNumberOfShards: 100) { }
+
+    public string EntityId(object message) 
+    {
+        return message switch
+        {
+            string sharded => sharded,
+            ShardingEnvelope e => e.EntityId,
+            ShardRegion.StartEntity start => start.EntityId,
+            _ => null,
+        };
+    } 
+}
+```
+
+## Resolution
+
+Akka.Analyzers comes with a code fix for this issue, which if accepted by the end user, will rewrite the previous example to the following:
+
+```csharp
+using Akka.Cluster.Sharding;
+
+public sealed class MessageExtractor : HashCodeMessageExtractor
+{
+    public MessageExtractor() : base(maxNumberOfShards: 100) { }
+
+public string EntityId(object message) 
+    {
+        return message switch
+        {
+            string sharded => sharded,
+            _ => null,
+        };
+    } 
+}
+```

docs/articles/debugging/rules/toc.yml

@@ -3,4 +3,6 @@
 - name: AK1001
   href: AK1001.md
 - name: AK2000
-  href: AK2000.md
+  href: AK2000.md
+- name: AK2001
+  href: AK2001.md

src/Directory.Build.props

@@ -70,7 +70,7 @@ If you want to see the [full set of changes made in Akka.NET v1.5.14, click here
 | 1       | 1    | 1    | szaliszali          |</PackageReleaseNotes>
   </PropertyGroup>
   <ItemGroup Label="Analyzers">
-    <PackageReference Include="Akka.Analyzers" Version="0.1.2" PrivateAssets="all" />
+    <PackageReference Include="Akka.Analyzers" Version="0.2.0" PrivateAssets="all" />
   </ItemGroup>
   <!-- SourceLink support for all Akka.NET projects -->
   <ItemGroup>