[PATCH] debugsetparent: document one common caveat specifically

[Martin von Zweigbergk]

# HG changeset patch
# User Martin von Zweigbergk <martinvonz at google.com>
# Date 1424893154 28800
#      Wed Feb 25 11:39:14 2015 -0800
# Node ID f4138e611d14b8e9bc9e2dc8417a094ddb83173a
# Parent  e7785573a4af258101d0cc0b0947a6de65273096
debugsetparent: document one common caveat specifically

After calling debugsetparent, it's quite common that status is
incorrect. The command's help text already says that it should be used
with care, but let's describe this caveat explicitly since it's
probably the most common one.

diff -r e7785573a4af -r f4138e611d14 mercurial/commands.py
--- a/mercurial/commands.py	Wed Feb 18 16:45:16 2015 -0800
+++ b/mercurial/commands.py	Wed Feb 25 11:39:14 2015 -0800
@@ -2893,7 +2893,8 @@
     """manually set the parents of the current working directory
 
     This is useful for writing repository conversion tools, but should
-    be used with care.
+    be used with care. For example, neither the working copy nor the dirstate
+    is updated, so file status may be incorrect after running this command.
 
     Returns 0 on success.
     """