putchunks: increase the default segment size to 8000 bytes

Change-Id: I16c2e21f168c77259d6bdc47b86fceb258521517
diff --git a/manpages/ndnputchunks.rst b/manpages/ndnputchunks.rst
index d87d8a5..6a3b8af 100644
--- a/manpages/ndnputchunks.rst
+++ b/manpages/ndnputchunks.rst
@@ -26,11 +26,12 @@
 
 .. option:: -f, --freshness MILLISECS
 
-    FreshnessPeriod of the published Data packets, in milliseconds. Default = 10000 [ms].
+    FreshnessPeriod of the published Data packets, in milliseconds.
+    The default is 10000 (10 seconds).
 
 .. option:: -s, --size BYTES
 
-    Maximum chunk size, in bytes. Default = 4400 [bytes].
+    Maximum chunk size, in bytes. The default is 8000 bytes.
 
 .. option:: -N, --naming-convention CONVENTION