gh-137533:move notes under json.dumps() to module-level documents

Author: Rov-Waff

Doc/library/json.rst

@@ -147,9 +147,10 @@ See :ref:`json-commandline` for detailed documentation.
    default.  Order is only lost if the underlying containers are unordered.
 
 .. note::
-   Per :rfc:`7159`, JSON objects' keys must be strings.
-   This module's encoder converts Python dictionary's keys to strings,
-   and its decoder produces Python dictionaries with string keys.
+   :rfc:`7159` requires that keys in key/value pairs of JSON are always of the
+   type :class:`str`. When a dictionary is converted into JSON, all the keys
+   of the dictionary arecoerced to strings.When a JSON object is converted into
+   dictionaries,all the keys of the dictionary are strings.
 
 Basic Usage
 -----------