Remove unused label

Author: maxrjones

docs/user-guide/arrays.md

@@ -540,7 +540,7 @@ bar[:] = np.arange(100)
 print(root.tree())
 ```
 
-## Sharding {#user-guide-sharding}
+## Sharding
 
 Using small chunk shapes in very large arrays can lead to a very large number of chunks.
 This can become a performance issue for file systems and object storage.