Merge pull request #17773 from PuchatekwSzortach/session_run_document…

…ation

Updated tf.Session.run(...) documentation

tensorflow/python/client/session.py

@@ -889,6 +889,8 @@ def run(self, fetches, feed_dict=None, options=None, run_metadata=None):
       Either a single value if `fetches` is a single graph element, or
       a list of values if `fetches` is a list, or a dictionary with the
       same keys as `fetches` if that is a dictionary (described above).
+      Order in which `fetches` operations are evaluated inside the call
+      is undefined.
 
     Raises:
       RuntimeError: If this `Session` is in an invalid state (e.g. has been