DOCSP-28696 review update (#253)

Author: Dave Cuthbert

source/reference/compatibility.txt

@@ -151,7 +151,7 @@ These :ref:`ObjectId() <server-objectid>` methods work differently in
    * - ``ObjectId.valueOf()``
      - | Returns the value of ``ObjectId.str``:
        | ``6419ccfce40afaf9317567b7``
-     - | Returns the value of ``ObjectId.self``:
+     - | Returns a formatted string:
        | ``ObjectId("6419ccfce40afaf9317567b7")``
 
    * - ``ObjectId.toString()``