Issue #19789: Clarified documentation for logging.disable.

Doc/library/logging.rst

@@ -987,8 +987,10 @@ functions.
    effect is to disable all logging calls of severity *lvl* and below, so that
    if you call it with a value of INFO, then all INFO and DEBUG events would be
    discarded, whereas those of severity WARNING and above would be processed
-   according to the logger's effective level. To undo the effect of a call to
-   ``logging.disable(lvl)``, call ``logging.disable(logging.NOTSET)``.
+   according to the logger's effective level. If
+   ``logging.disable(logging.NOTSET)`` is called, it effectively removes this
+   overriding level, so that logging output again depends on the effective
+   levels of individual loggers.
 
 
 .. function:: addLevelName(lvl, levelName)