Put action encoder documentation back

lib/src/action_encoder.dart

@@ -5,6 +5,19 @@ part of redux_remote_devtools;
 typedef ActionEncoder = String Function(dynamic action);
 
 /// An action encoder that converts an action to stringified JSON
+///
+/// Encodes an action as stringified JSON
+///
+/// Uses the form:
+///
+/// {
+///   "type": "TYPE"
+///   "payload": jsonEncode(action)
+/// }
+///
+/// Action type is set to be the class name for class based
+/// actions, or an enum value for enum actions
+///
 ActionEncoder JsonActionEncoder = (dynamic action) {
   /// Gets a type name for the action, based on the class name or value
   String getActionType(dynamic action) {