[SPARK-36288][DOCS][PYTHON] Update API usage on pyspark pandas documents

### What changes were proposed in this pull request?

Update api usage examples on PySpark pandas API documents.

### Why are the changes needed?

If users try to use PySpark pandas API from the document, they will see some API deprication warnings.
It is kind for users to update those documents to avoid confusion.

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

```
make html
```

Closes #33519 from yoda-mon/update-pyspark-configurations.

Authored-by: Leona <yodal@oss.nttdata.com>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>

python/docs/source/user_guide/pandas_on_spark/best_practices.rst

@@ -34,7 +34,7 @@ it can be set into Spark session as below:
 
    from pyspark.sql import SparkSession
    builder = SparkSession.builder.appName("pandas-on-spark")
-   builder = builder.config("spark.sql.execution.arrow.enabled", "true")
+   builder = builder.config("spark.sql.execution.arrow.pyspark.enabled", "true")
    # Pandas API on Spark automatically uses this Spark session with the configurations set.
    builder.getOrCreate()
 

python/docs/source/user_guide/pandas_on_spark/from_to_dbms.rst

@@ -95,7 +95,7 @@ You can also write it back to the ``stocks`` table as below:
 .. code-block:: python
 
     df.price += 1
-    df.to_spark_io(
+    df.spark.to_spark_io(
         format="jdbc", mode="append",
         dbtable="stocks", url="jdbc:sqlite:{}/example.db".format(os.getcwd()))
     ps.read_sql("stocks", con="jdbc:sqlite:{}/example.db".format(os.getcwd()))