docs: remove dictionary functions (#2999)

Author: BohuTANG

docs/en/sql-reference/20-sql-functions/19-dictionary-functions/_category_.json

@@ -69,6 +69,6 @@ Databend provides comprehensive SQL functions for all types of data processing.
 | [Interval Functions](./05-interval-functions/index.md) | Time unit conversion and interval creation |
 | [Sequence Functions](./18-sequence-functions/index.md) | Auto-incrementing sequence value generation |
 | [Data Anonymization Functions](./19-data-anonymization-functions/index.md) | Data masking and anonymization utilities |
-| [Dictionary Functions](./19-dictionary-functions/index.md) | Real-time external data source queries (MySQL, Redis) |
+
 | [Test Functions](./19-test-functions/index.md) | Testing and debugging utilities |
 | [Other Functions](./20-other-functions/index.md) | Miscellaneous helpers and utilities |