[PATCH 1 of 4] windows: augment docstring of `winstdout` class

[Manuel Jacob]

# HG changeset patch
# User Manuel Jacob <me at manueljacob.de>
# Date 1594948349 -7200
#      Fri Jul 17 03:12:29 2020 +0200
# Node ID 217660a6547cb5db3a53456998032cbfcd069967
# Parent  f55099982bc517c349bf46fab53b8696f0615c17
# EXP-Topic stdio-broken_pipe
windows: augment docstring of `winstdout` class

diff --git a/mercurial/windows.py b/mercurial/windows.py
--- a/mercurial/windows.py
+++ b/mercurial/windows.py
@@ -187,7 +187,13 @@
 
 
 class winstdout(object):
-    '''stdout on windows misbehaves if sent through a pipe'''
+    '''Some files on Windows misbehave.
+
+    When writing to a broken pipe, EINVAL instead of EPIPE may be raised.
+
+    When writing too many bytes to a console at the same, a "Not enough space"
+    error may happen. Python 3 already works around that.
+    '''
 
     def __init__(self, fp):
         self.fp = fp