fix doctest too

Author: sycai

bigframes/bigquery/_operations/ai.py

@@ -47,13 +47,13 @@ def generate_bool(
         ...     "col_1": ["apple", "bear", "pear"],
         ...     "col_2": ["fruit", "animal", "animal"]
         ... })
-        >>> bbq.ai_generate_bool((df["col_1"], " is a ", df["col_2"]))
+        >>> bbq.ai.generate_bool((df["col_1"], " is a ", df["col_2"]))
         0    {'result': True, 'full_response': '{"candidate...
         1    {'result': True, 'full_response': '{"candidate...
         2    {'result': False, 'full_response': '{"candidat...
         dtype: struct<result: bool, full_response: string, status: string>[pyarrow]
 
-        >>> bbq.ai_generate_bool((df["col_1"], " is a ", df["col_2"])).struct.field("result")
+        >>> bbq.ai.generate_bool((df["col_1"], " is a ", df["col_2"])).struct.field("result")
         0     True
         1     True
         2    False
@@ -66,7 +66,7 @@ def generate_bool(
         ...         }
         ...     }
         ... }
-        >>> bbq.ai_generate_bool(
+        >>> bbq.ai.generate_bool(
         ...     (df["col_1"], " is a ", df["col_2"]),
         ...     endpoint="gemini-2.5-pro",
         ...     model_params=model_params,