[Python-checkins] bpo-43126: Expand docs on io.IOBase.readlines() method (GH-27061) (#27114)

[ambv]

https://github.com/python/cpython/commit/a3d20bfee38c71df88d69064d47fe98a1d59e624
commit: a3d20bfee38c71df88d69064d47fe98a1d59e624
branch: 3.9
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: ambv <lukasz at langa.pl>
date: 2021-07-13T16:41:31+02:00
summary:

bpo-43126: Expand docs on io.IOBase.readlines() method (GH-27061) (#27114)

Co-authored-by: Łukasz Langa <lukasz at langa.pl>
(cherry picked from commit 3b5b99da4b256a31933112f4a2385386149c19e1)

Co-authored-by: andrei kulakov <andrei.avk at gmail.com>

files:
M Doc/library/io.rst

diff --git a/Doc/library/io.rst b/Doc/library/io.rst
index 96e02e839ae65..0ff05cfc0e091 100644
--- a/Doc/library/io.rst
+++ b/Doc/library/io.rst
@@ -315,6 +315,9 @@ I/O Base Classes
       to control the number of lines read: no more lines will be read if the
       total size (in bytes/characters) of all lines so far exceeds *hint*.
 
+      *hint* values of ``0`` or less, as well as ``None``, are treated as no
+      hint.
+
       Note that it's already possible to iterate on file objects using ``for
       line in file: ...`` without calling ``file.readlines()``.