Resolve "Feature: Send endpoint for attributes"

Closes #38 (closed)

ragconnect.base/src/main/jastadd/parser/RagConnect.parser

@@ -63,7 +63,7 @@ EndpointDefinition endpoint_definition_type
 
 EndpointTarget endpoint_target
   = ID.type_name DOT ID.child_name    {: return new UntypedEndpointTarget(type_name, child_name, false); :}
-  | ID.type_name DOT ID.child_name BRACKETS COLON ID.attribute_type_name
+  | ID.type_name DOT ID.child_name BRACKET_LEFT ID.attribute_type_name BRACKET_RIGHT
      {: return new UntypedEndpointTarget(type_name, child_name + ":" + attribute_type_name, true); :}
   | ID.type_name                      {: return new UntypedEndpointTarget(type_name, "", false); :}
 ;