docs: update procedure language support overview

Author: rain

docs/docs/00100-intro/00100-getting-started/00400-key-architecture.md

@@ -345,9 +345,21 @@ ctx.procedures.makeRequest().then(
 </TabItem>
 <TabItem value="csharp" label="C#">
 
-C# modules currently cannot define procedures. Support for defining procedures in C# modules will be released shortly.
+C# modules can define procedures, but procedure support is currently unstable.
+To use it, add `#pragma warning disable STDB_UNSTABLE` at the top of your file.
 
-A C# [client](#client) can call a procedure defined by a Rust or TypeScript module:
+```csharp
+#pragma warning disable STDB_UNSTABLE
+
+[SpacetimeDB.Procedure]
+public static string MakeRequest(ProcedureContext ctx)
+{
+    // ...
+    return "result";
+}
+```
+
+A C# [client](#client) can call a procedure defined by a module:
 
 ```csharp
 void Main()
@@ -384,7 +396,7 @@ Because procedures are unstable, Rust modules that define them must opt in to th
 
 ```toml
 [dependencies]
-spacetimedb = { version = "1.x", features = ["unstable"] }
+spacetimedb = { version = "2.*", features = ["unstable"] }
 ```
 
 Then, that module can define a procedure:
@@ -436,7 +448,7 @@ Use the other tabs (TypeScript/C#/Rust/Unreal C++/Blueprint) for client call exa
 </TabItem>
 <TabItem value="cpp-unreal" label="Unreal C++">
 
-An Unreal C++ [client](#client) can call a procedure defined by a Rust or TypeScript module:
+An Unreal C++ [client](#client) can call a procedure defined by a module:
 
 ```cpp
 {
@@ -468,7 +480,7 @@ void AGameManager::OnMakeRequestComplete(const FProcedureEventContext& Context,
 </TabItem>
 <TabItem value="blueprint" label="Unreal Blueprint">
 
-An Unreal [client](#client) can call a procedure defined by a Rust or TypeScript module:
+An Unreal [client](#client) can call a procedure defined by a module:
 
 ![MakeRequest without callback](/images/unreal/intro/ue-blueprint-makerequest-nocallback.png)