Issue #16701: Document += and *= for mutable sequences
diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index c3dc63d..ce3c532 100644
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -1063,10 +1063,14 @@
| ``s.copy()`` | creates a shallow copy of ``s``| \(5) |
| | (same as ``s[:]``) | |
+------------------------------+--------------------------------+---------------------+
-| ``s.extend(t)`` | extends *s* with the | |
-| | contents of *t* (same as | |
+| ``s.extend(t)`` or | extends *s* with the | |
+| ``s += t`` | contents of *t* (for the | |
+| | most part the same as | |
| | ``s[len(s):len(s)] = t``) | |
+------------------------------+--------------------------------+---------------------+
+| ``s *= n`` | updates *s* with its contents | \(6) |
+| | repeated *n* times | |
++------------------------------+--------------------------------+---------------------+
| ``s.insert(i, x)`` | inserts *x* into *s* at the | |
| | index given by *i* | |
| | (same as ``s[i:i] = [x]``) | |
@@ -1107,6 +1111,12 @@
.. versionadded:: 3.3
:meth:`clear` and :meth:`!copy` methods.
+(6)
+ The value *n* is an integer, or an object implementing
+ :meth:`~object.__index__`. Zero and negative values of *n* clear
+ the sequence. Items in the sequence are not copied; they are referenced
+ multiple times, as explained for ``s * n`` under :ref:`typesseq-common`.
+
.. _typesseq-list: