DOC: relation between timeout http-request and option http-buffer-request

The documentation missed the explanation and relation between the
timeout http-request and option http-buffer-request.
Combined together, it helps protecting against slow POST types of
attacks.

[wt: backport to 1.6]
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 997d838..e06e01d 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -5059,7 +5059,7 @@
   the frontend and the backend, so this should definitely not be used by
   default.
 
-  See also : "option http-no-delay"
+  See also : "option http-no-delay", "timeout http-request"
 
 
 option http-ignore-probes
@@ -9133,9 +9133,11 @@
   code using "option http-ignore-probes" or "errorfile 408 /dev/null". See
   more details in the explanations of the "cR" termination code in section 8.5.
 
-  Note that this timeout only applies to the header part of the request, and
-  not to any data. As soon as the empty line is received, this timeout is not
-  used anymore. It is used again on keep-alive connections to wait for a second
+  By default, this timeout only applies to the header part of the request,
+  and not to any data. As soon as the empty line is received, this timeout is
+  not used anymore. When combined with "option http-buffer-request", this
+  timeout also applies to the body of the request..
+  It is used again on keep-alive connections to wait for a second
   request if "timeout http-keep-alive" is not set.
 
   Generally it is enough to set it to a few seconds, as most clients send the
@@ -9150,7 +9152,7 @@
   timeout will be used.
 
   See also : "errorfile", "http-ignore-probes", "timeout http-keep-alive", and
-             "timeout client".
+             "timeout client", "option http-buffer-request".
 
 
 timeout queue <timeout>