docs: prevent warnings due to autosectionlabel

Changeset 58ad30cf91f0 ("docs: fix reference to core-api/namespaces.rst")
enabled a new feature at Sphinx: it will now generate index for each
document title, plus to each chapter inside it.

There's a drawback, though: one document cannot have two sections
with the same name anymore.

A followup patch will change the logic of autosectionlabel to
avoid most creating references for every single section title,
but still we need to be able to reference the chapters inside
a document.

There are a few places where there are two chapters with the
same name. This patch renames one of the chapters, in order to
avoid symbol conflict within the same document.

PS.: as I don't speach Chinese, I had some help from a friend
(Wen Liu) at the Chinese translation for "publishing patches"
for this document:

	Documentation/translations/zh_CN/process/5.Posting.rst

Fixes: 58ad30cf91f0 ("docs: fix reference to core-api/namespaces.rst")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/2bffb91e4a63d41bf5fae1c23e1e8b3bba0b8806.1584716446.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/networking/snmp_counter.rst b/Documentation/networking/snmp_counter.rst
index 38a4edc..10e1109 100644
--- a/Documentation/networking/snmp_counter.rst
+++ b/Documentation/networking/snmp_counter.rst
@@ -908,8 +908,8 @@
 
 A packet loss is detected and recovered by TLP.
 
-TCP Fast Open
-=============
+TCP Fast Open description
+=========================
 TCP Fast Open is a technology which allows data transfer before the
 3-way handshake complete. Please refer the `TCP Fast Open wiki`_ for a
 general description.