docs: update example to use static Register/Unregister

README.md

@@ -39,7 +39,7 @@ Add it as a dependency in your `modinfo.json`:
 ```json
 "dependencies": {
     "game": "1.22.3",
-    "commandhook": "2.0.0"
+    "commandhook": "2.1.0"
 }
 ```
 
@@ -116,16 +116,16 @@ Register it once your mod starts, unregister it on dispose:
 ```csharp
 public override void StartServerSide(ICoreServerAPI api)
 {
-    // CommandHookModSystem.Instance is null if CommandHook isn't loaded,
-    // hence the ?. Register your listener once, here.
-    CommandHookModSystem.Instance?.Register(myListener);
+    // Register your listener once, here. No-ops silently if CommandHook
+    // isn't loaded.
+    CommandHookModSystem.Register(myListener);
 }
 
 public override void Dispose()
 {
     // Always unregister on dispose, otherwise a stale listener stays in
     // the dispatch table after your mod is gone.
-    CommandHookModSystem.Instance?.Unregister(myListener);
+    CommandHookModSystem.Unregister(myListener);
 }
 ```