[keras] documentation of jank mechanism for PatientTracker

keras.py

@@ -760,6 +760,13 @@ class BestTracker(tf.keras.callbacks.Callback):
 
 
 class PatientTracker(BestTracker):
+    """
+    Jank:
+        All PatientTrackers can communicate over the jank variable:
+        If one PatientTracker triggers, all other PatientTrackers may not trigger for the number of epochs given by their jank.
+        In order to participate in the jank mechanism, the jank of a PatientTracker must be finite (e.g. jank -1).
+    """
+
     def __init__(
         self,
         patience=10,