docs: Document PEP487 __set_name__ implementation.

Signed-off-by: Anson Mansfield <[email protected]>

Author: AJMansfield

docs/differences/python_36.rst

@@ -25,7 +25,8 @@ Python 3.6 beta 1 was released on 12 Sep 2016, and a summary of the new features
   +--------------------------------------------------------+--------------------------------------------------+-----------------+
   | `PEP 468 <https://www.python.org/dev/peps/pep-0468/>`_ | Preserving the order of *kwargs* in a function   |                 |
   +--------------------------------------------------------+--------------------------------------------------+-----------------+
-  | `PEP 487 <https://www.python.org/dev/peps/pep-0487/>`_ | Simpler customization of class creation          |                 |
+  | `PEP 487 <https://www.python.org/dev/peps/pep-0487/>`_ | Simpler customization of class creation          | Partial         |
+  |                                                        |                                                  | [#setname]_     |
   +--------------------------------------------------------+--------------------------------------------------+-----------------+
   | `PEP 520 <https://www.python.org/dev/peps/pep-0520/>`_ | Preserving Class Attribute Definition Order      |                 |
   +--------------------------------------------------------+--------------------------------------------------+-----------------+
@@ -198,3 +199,7 @@ Changes to built-in modules:
   +--------------------------------------------------------------------------------------------------------------+----------------+
   | The *compress()* and *decompress()* functions now accept keyword arguments                                   |                |
   +--------------------------------------------------------------------------------------------------------------+----------------+
+
+.. rubric:: Notes
+
+.. [#setname] Currently, only :func:`__set_name__` is implemented.

py/mpconfig.h

@@ -1129,7 +1129,7 @@ typedef time_t mp_timestamp_t;
 #define MICROPY_PY_FUNCTION_ATTRS_CODE (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_FULL_FEATURES)
 #endif
 
-// Whether to support the descriptors __get__, __set__, __delete__
+// Whether to support the descriptors __get__, __set__, __delete__, __set_name__
 // This costs some code size and makes load/store/delete of instance
 // attributes slower for the classes that use this feature
 #ifndef MICROPY_PY_DESCRIPTORS