remove the general javascript variable arguments per scott's comment

Author: kay-kim

source/reference/method/cursor.forEach.txt

@@ -16,30 +16,7 @@ cursor.forEach()
 
           JavaScript function to apply to each document from the
           cursor. The ``<function>`` signature includes a single argument
-          that is passed the current document to process, as in the
-          following prototype:
-
-          .. code-block:: javascript
-
-             function(doc) {
-                ...
-             }
-
-          However, if the signature is missing the argument, you can
-          access the document using the reserved
-          ``arguments`` [#arguments]_ variable within the function,
-          specifically ``arguments[0]``, as in the following prototype:
-
-          .. code-block:: javascript
-
-             function() {
-                doc = arguments[0];
-                ...
-             }
-
-          .. [#arguments] The ``arguments`` variable is an array
-             and thus, you can access ``arguments.length`` attribute to
-             determine the number of arguments.
+          that is passed the current document to process.
 
    The following example invokes the :method:`~cursor.forEach()` method
    on the cursor returned by :method:`~db.collection.find()` to print