docs(clickhouse): remove unsupported DateTime64 type-mapping row

ClickHouse schema inference (get_schema in clickhouseconn.rs) uses the
string-based map_clickhouse_type_to_arrow, which only matches the literal
"DateTime" — a DateTime64 column reports its type as "DateTime64(p[, tz])"
in system.columns and falls through to the Unsupported error, so a table
with a DateTime64 column cannot be registered. Completes #1794, which
removed the sibling unsupported Date32 row added by the same PR (#1701)
but missed DateTime64.

Author: claudespice

website/docs/components/data-connectors/clickhouse.md

@@ -90,7 +90,6 @@ The table below shows the ClickHouse data types supported, along with the type m
 | `UUID`           | `Utf8`                      |
 | `Date`           | `Date32`                    |
 | `DateTime`       | `Timestamp(Second, None)`   |
-| `DateTime64`     | `Timestamp(Second, None)`   |
 | `Nullable(T)`    | Mapped inner type `T`       |
 
 ## Examples

website/versioned_docs/version-2.0.x/components/data-connectors/clickhouse.md

@@ -90,7 +90,6 @@ The table below shows the ClickHouse data types supported, along with the type m
 | `UUID`           | `Utf8`                      |
 | `Date`           | `Date32`                    |
 | `DateTime`       | `Timestamp(Second, None)`   |
-| `DateTime64`     | `Timestamp(Second, None)`   |
 | `Nullable(T)`    | Mapped inner type `T`       |
 
 ## Examples