Clarify ClickPipes JSON Variant requirements

Author: genzgd

docs/integrations/data-ingestion/clickpipes/kafka/03_reference.md

@@ -77,8 +77,8 @@ ClickPipes supports the Variant type in the following circumstances:
 - Avro Unions.  If your Avro schema contains a union with multiple non-null types, ClickPipes will infer the
   appropriate variant type.  Variant types are not otherwise supported for Avro data.
 - JSON fields.  You can manually specify a Variant type (such as `Variant(String, Int64, DateTime)`) for any JSON field
-  in the source data stream.  Because of the way ClickPipes determines the correct variant subtype to use, only one integer or datetime
-  type can be used in the Variant definition - for example, `Variant(Int64, UInt32)` is not supported.
+  in the source data stream.  Complex subtypes (arrays/maps/tuples) are not supported.  In addition, because of the way ClickPipes determines
+  the correct variant subtype to use, only one integer or datetime type can be used in the Variant definition - for example, `Variant(Int64, UInt32)` is not supported.
 
 #### JSON type support {#json-type-support}
 ClickPipes support the JSON type in the following circumstances: