[docs] add missing code block in cast_examples.md (#10201)

Author: blinkov

ydb/docs/en/core/yql/reference/yql-core/_includes/cast_examples.md

@@ -1,3 +1,5 @@
+
+```yql
 SELECT
     CAST("12345" AS Double),                -- 12345.0
     CAST(1.2345 AS Uint8),                  -- 1
@@ -11,3 +13,4 @@ SELECT
         --The item type is not optional: the failed item has been deleted.
     CAST(255 AS Uint8),                     -- 255
     CAST(256 AS Uint8) IS NULL -- true, out of range
+```

ydb/docs/en/core/yql/reference/yql-core/syntax/_includes/expressions/cast.md

@@ -1,5 +1,7 @@
 ## CAST {#cast}
 
+<!-- markdownlint-disable blanks-around-fences -->
+
 Tries to cast the value to the specified type. The attempt may fail and return `NULL`. When used with numbers, it may lose precision or most significant bits.
 {% if feature_column_container_type %}
 For lists and dictionaries, it can either delete or replace with `NULL` the elements whose conversion failed.
@@ -12,4 +14,3 @@ For more information about casting rules, see [here](../../../types/cast.md).
 ### Examples
 
 {% include [cast_examples](../../../_includes/cast_examples.md) %}
-