doc: update co_flags reference (#132300)

Co-authored-by: Hugo van Kemenade <[email protected]>

Author: methane

Doc/reference/datamodel.rst

@@ -1526,18 +1526,17 @@ positional arguments; bit ``0x08`` is set if the function uses the
 if the function is a generator. See :ref:`inspect-module-co-flags` for details
 on the semantics of each flags that might be present.
 
-Future feature declarations (``from __future__ import division``) also use bits
+Future feature declarations (for example, ``from __future__ import division``) also use bits
 in :attr:`~codeobject.co_flags` to indicate whether a code object was compiled with a
-particular feature enabled: bit ``0x2000`` is set if the function was compiled
-with future division enabled; bits ``0x10`` and ``0x1000`` were used in earlier
-versions of Python.
+particular feature enabled. See :attr:`~__future__._Feature.compiler_flag`.
 
 Other bits in :attr:`~codeobject.co_flags` are reserved for internal use.
 
 .. index:: single: documentation string
 
 If a code object represents a function and has a docstring,
-the first item in :attr:`~codeobject.co_consts` is
+the :data:`~inspect.CO_HAS_DOCSTRING` bit is set in :attr:`~codeobject.co_flags`
+and the first item in :attr:`~codeobject.co_consts` is
 the docstring of the function.
 
 Methods on code objects