Merge pull request #553 from epc/DOCS-978-mongodb-232

DOCS-978 fix error introduced by versionadded in table

Author: Ed Costello

source/reference/mongo-shell-reference.txt

@@ -70,11 +70,11 @@ displays some common help methods and commands:
      - Show help on collection methods. The ``<collection>`` can be the
        name of an existing collection or a non-existing collection.
 
-   .. versionadded:: 2.3.1
 
    * - ``show databases``
 
-     - Print a list of all databases on the server.
+     - .. versionadded:: 2.3.1
+          Print a list of all databases on the server.
 
    * - ``show dbs``