fixes NN_MAXTTL typo in docs for nn_{get|set}sockopt
NN_TTL never existed, we're looking for NN_MAXTTL
diff --git a/doc/nn_getsockopt.adoc b/doc/nn_getsockopt.adoc
index 0a20a02..c1a7c47 100644
--- a/doc/nn_getsockopt.adoc
+++ b/doc/nn_getsockopt.adoc
@@ -112,7 +112,7 @@
Socket name for error reporting and statistics. The type of the option
is string. Default value is "N" where N is socket integer.
*This option is experimental, see <<nn_env#,nn_env(7)>> for details*
-*NN_TTL*::
+*NN_MAXTTL*::
Retrieves the maximum number of "hops" a message can go through before
it is dropped. Each time the message is received (for example via
the <<nn_device#,nn_device(3)>> function) counts as a single hop.
diff --git a/doc/nn_setsockopt.adoc b/doc/nn_setsockopt.adoc
index 5deb41e..3e8aff6 100644
--- a/doc/nn_setsockopt.adoc
+++ b/doc/nn_setsockopt.adoc
@@ -85,7 +85,7 @@
Socket name for error reporting and statistics. The type of the option
is string. Default value is "socket.N" where N is socket integer.
*This option is experimental, see <<nn_env#,nn_env(7)>> for details*
-*NN_TTL*::
+*NN_MAXTTL*::
Sets the maximum number of "hops" a message can go through before
it is dropped. Each time the message is received (for example via
the <<nn_device#,nn_device(3)>> function) counts as a single hop.
