CLIENT-2785 Update map key doc to say that only as_string, as_integer…

… and as_bytes types are allowed as map keys.

src/include/aerospike/as_map_operations.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2023 Aerospike, Inc.
+ * Copyright 2008-2024 Aerospike, Inc.
  *
  * Portions may be licensed to Aerospike, Inc. under one or more contributor
  * license agreements.
@@ -26,9 +26,10 @@
  * <li>as_string</li>
  * <li>as_integer</li>
  * <li>as_bytes</li>
- * <li>as_list</li>
  * </ul>
  *
+ * The server will validate map key types in an upcoming release.
+ *
  * All maps maintain an index and a rank.  The index is the item offset from the start of the map,
  * for both unordered and ordered maps.  The rank is the sorted index of the value component.
  * Map supports negative indexing for index and rank.