add some missing docs

Author: JW Wesson

src/main/java/com/textkernel/tx/models/api/parsing/FlexRequestDataType.java

@@ -4,9 +4,14 @@
  * Possible data types for FlexRequests
  */
 public enum FlexRequestDataType {
+    /** Text/string response expected */
     Text,
+    /** Numeric response expected */
     Numeric,
+    /** Boolean response expected */
     Bool,
+    /** List of text responses expected */
     List,
+    /** Text response should be from a provided list of options. See {@link FlexRequest#EnumerationValues} */
     Enumeration
 }