DOCSP-22047 clarify edit autoload (#202)

* DOCSP-22047 Clarify edit autoload

* DOCSP-22047 Clarify edit autoload

* Review updates

Author: Dave

source/reference/editor-mode.txt

@@ -194,10 +194,11 @@ The ``nano`` editor will open when you run ``edit`` in the
 Editing a Command
 ~~~~~~~~~~~~~~~~~
 
-Use ``edit`` to modify the last edit. 
+Use ``edit`` to start an editing session. If the editor was already
+used in the current console session, the editor opens the last edit. 
 
-This statement was just written in the external editor. Unfortunately,
-it has a syntax error. The highlighted line is missing a comma: 
+The following statement has a syntax error. The highlighted line is
+missing a comma:
 
 .. code-block:: javascript
    :emphasize-lines: 4
@@ -211,8 +212,18 @@ it has a syntax error. The highlighted line is missing a comma:
       { "name": "Paola", "group": "marketing" }
    ] )
 
-Enter ``edit`` without any arguments to re-edit the command. The
-external editor reloads the last edit.
+To set up the example:
+
+#. Copy the example code.
+#. Enter ``edit`` to start an editing session. 
+#. Paste the example code into the editor.
+#. Exit the editor. 
+#. Press ``enter``.
+
+When you exit the editor, it copies the example code to the command
+line. :binary:`mongosh` returns an error when the code runs.
+
+To reload the example code, enter ``edit`` without any arguments.
 
 .. code-block:: javascript
    :copyable: false