samples: mqtt_publisher: fixed typo

Also fix console syntax adding prompt: $

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/samples/net/mqtt_publisher/README.rst b/samples/net/mqtt_publisher/README.rst
index acebde3..30990a2 100644
--- a/samples/net/mqtt_publisher/README.rst
+++ b/samples/net/mqtt_publisher/README.rst
@@ -98,19 +98,19 @@
 
 .. code-block:: console
 
-	make BOARD=frdm_k64f
+	$ make BOARD=frdm_k64f
 
 Open another terminal window and type:
 
 .. code-block:: console
 
-	sudo mosquitto -v -p 1883
+	$ sudo mosquitto -v -p 1883
 
 Open another terminal window and type:
 
 .. code-block:: console
 
-	mosquito_sub -t sensors
+	$ mosquitto_sub -t sensors
 
 Sample output
 =============
@@ -185,7 +185,7 @@
 
 .. code-block:: console
 
-	mosquitto_sub -t sensors
+	$ mosquitto_sub -t sensors
 	DOORS:OPEN_QoS0
 	DOORS:OPEN_QoS1
 	DOORS:OPEN_QoS2
@@ -206,7 +206,7 @@
 
 .. code-block:: console
 
-	sudo mosquitto -v
+	$ sudo mosquitto -v
 	1485663791: mosquitto version 1.3.4 (build date 2014-08-17 00:14:52-0300) starting
 	1485663791: Using default config.
 	1485663791: Opening ipv4 listen socket on port 1883.