MINOR: da: Using ARG12 macro for the sample fetch and the convertor.

Regarding the minor update introduced in the
cd6c3c7cb4fdc9cf694b62241840e3fea30e03dd commit, the DeviceAtlas
module is now able to use up to 12 device properties via the
new ARG12 macro.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 6b29df4..dc1a3fc 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -11678,14 +11678,14 @@
   input, and to emit a string made of the concatenation of the properties
   enumerated in argument, delimited by the separator defined by the global
   keyword "deviceatlas-property-separator", or by default the pipe character
-  ('|'). There's a limit of 5 different properties imposed by the haproxy
+  ('|'). There's a limit of 12 different properties imposed by the haproxy
   configuration language.
 
   Example:
     frontend www
       bind *:8881
       default_backend servers
-      http-request set-header X-DeviceAtlas-Data %[req.fhdr(User-Agent),da-csv(primaryHardwareType,osName,osVersion,browserName,browserVersion)]
+      http-request set-header X-DeviceAtlas-Data %[req.fhdr(User-Agent),da-csv(primaryHardwareType,osName,osVersion,browserName,browserVersion,browserRenderingEngine)]
 
 debug
   This converter is used as debug tool. It dumps on screen the content and the