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

akulakov · ambv · web-flow · commit 3b5b99da4b25 · 2021-07-13T16:07:56.000+02:00
Co-authored-by: Łukasz Langa &lt;lukasz@langa.pl&gt;
diff --git a/Doc/library/io.rst b/Doc/library/io.rst
@@ -391,6 +391,9 @@ 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()``.
 
