Added missing anchor to section

Docs/Architecture.md

@@ -45,7 +45,7 @@ Always use the batch adding functions when possible! Adding many bodies, one at
 
 You can call AddBody, RemoveBody, AddBody, RemoveBody to temporarily remove and later reinsert a body into the simulation.
 
-## Multithreaded Access
+## Multithreaded Access {#multi-threaded-access}
 
 Jolt is designed to be accessed from multiple threads so the body interface comes in two flavors: A locking and a non-locking variant. The locking variant uses a mutex array (a fixed size array of mutexes, bodies are associated with a mutex through hashing and multiple bodies use the same mutex, see [MutexArray](@ref MutexArray)) to prevent concurrent access to the same body. The non-locking variant doesn't use mutexes, so requires the user to be careful.