Define what “updating” means in docs for open (#19627).
Original patch by Lina Clark.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 3b3c7dd..dec76d3 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -880,8 +880,8 @@
to use the system default, which is usually line buffered for tty devices and
fully buffered for other files. If omitted, the system default is used. [#]_
- Modes ``'r+'``, ``'w+'`` and ``'a+'`` open the file for updating (note that
- ``'w+'`` truncates the file). Append ``'b'`` to the mode to open the file in
+ Modes ``'r+'``, ``'w+'`` and ``'a+'`` open the file for updating (reading and writing);
+ note that ``'w+'`` truncates the file. Append ``'b'`` to the mode to open the file in
binary mode, on systems that differentiate between binary and text files; on
systems that don't have this distinction, adding the ``'b'`` has no effect.