Update ZMQ Message Reference

ZMQ-Message-Reference.md

@@ -2,7 +2,7 @@ This page lists the JSON strings that can be sent to the ZMQ REQ/REP port in ord
 
 `[HEADER, DATA1 (, DATA2)]`
 
-where the data can either be an empty string, or a JSON structure, e.g.:
+where the data can either be an empty string, or a JSON list or structure, e.g.:
 
 `{"key1":"value1","key2":"value2","key3":"value3"}`
 
@@ -35,6 +35,12 @@ Published Messages:
 
 ## 'recordedChannels'
 
+Data is a list of strings that correspond to the names of the detectors to be enabled.
+
+```
+    msg = ['recordedChannels',   '["Counter0", "Counter1"]' ]
+```
+
 Reply Messages:
 - `["status","ok"]`
 
@@ -73,7 +79,7 @@ Reply Messages:
 * `"autoOff"`
 
 Example message contents for modifying the CoarseX positioner:
-
+```
     msg = ['modified positioner definition',
     '{
 	"name":"CoarseX",
@@ -94,7 +100,7 @@ Example message contents for modifying the CoarseX positioner:
 	"upperSoftLimit":1221.0,
 	"velocityUnit":"(/ms)"
 	}']
-
+```
 
 Successful modification of the positioner definition will result in the publication of the new positioner definition in full.