Remove duplicate mapping from iceberg docs

Author: auden-woolfson

presto-docs/src/main/sphinx/connector/iceberg.rst

@@ -1777,8 +1777,6 @@ Map of Iceberg types to the relevant PrestoDB types:
     - ``TIMESTAMP``
   * - ``TIMESTAMP``
     - ``TIMESTAMP_WITH_TIMEZONE``
-  * - ``STRING``
-    - ``VARCHAR``
   * - ``UUID``
     - ``UUID``
   * - ``LIST``