DOCSP-17205 dbase name in prompt (#224)

* DOCSP-17205 dbase name in prompt

* DOCSP-17205 dbase name in prompt

* Review feedback

Author: Dave Cuthbert

source/includes/examples/ex-display-dbname-and-hostname.rst

@@ -1,5 +1,6 @@
-To display the database and hostname in the :binary:`~bin.mongosh`
-prompt, use a function like this one:
+The current database name is part of the default ``mongosh`` prompt. To
+reformat the prompt to show the database and hostname, use a function
+like this one:
 
 .. code-block:: javascript
 

source/reference/customize-prompt.txt

@@ -11,9 +11,9 @@ Customize the :binary:`~bin.mongosh` Prompt
    :backlinks: none
    :depth: 1
 
-The ``prompt`` variable can store strings and JavaScript code to
-customize the :binary:`~bin.mongosh` prompt. Use a function that
-returns a string to display dynamic information in the prompt.
+By default the :binary:`~bin.mongosh` prompt includes the current
+database name. You can modify the ``prompt`` variable to display custom
+strings or to return dynamic information about your ``mongosh`` session.
 
 Custom prompts are not stored when you exit :binary:`~bin.mongosh`. To
 have a custom prompt persist through restarts, add the code for your