bpo-6634: [doc] clarify that sys.exit() does not always exit the inte…

…rpreter (GH-31639)

Doc/library/sys.rst

@@ -449,10 +449,7 @@ always available.
 
 .. function:: exit([arg])
 
-   Exit from Python.  This is implemented by raising the :exc:`SystemExit`
-   exception, so cleanup actions specified by finally clauses of :keyword:`try`
-   statements are honored, and it is possible to intercept the exit attempt at
-   an outer level.
+   Raise a :exc:`SystemExit` exception, signaling an intention to exit the interpreter.
 
    The optional argument *arg* can be an integer giving the exit status
    (defaulting to zero), or another type of object.  If it is an integer, zero
@@ -469,7 +466,8 @@ always available.
 
    Since :func:`exit` ultimately "only" raises an exception, it will only exit
    the process when called from the main thread, and the exception is not
-   intercepted.
+   intercepted. Cleanup actions specified by finally clauses of :keyword:`try` statements
+   are honored, and it is possible to intercept the exit attempt at an outer level.
 
    .. versionchanged:: 3.6
       If an error occurs in the cleanup after the Python interpreter