gh-92417: `subprocess` docs: remove note on compatibility with Python <3.5 (GH-92538) (GH-92973)

(cherry picked from commit 84b86000)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Doc/library/subprocess.rst

@@ -33,9 +33,6 @@ The recommended approach to invoking subprocesses is to use the :func:`run`
 function for all use cases it can handle. For more advanced use cases, the
 underlying :class:`Popen` interface can be used directly.
 
-The :func:`run` function was added in Python 3.5; if you need to retain
-compatibility with older versions, see the :ref:`call-function-trio` section.
-
 
 .. function:: run(args, *, stdin=None, input=None, stdout=None, stderr=None,\
                   capture_output=False, shell=False, cwd=None, timeout=None, \