[SPARK-33517][SQL][DOCS] Fix the correct menu items and page links in PySpark Usage Guide for Pandas with Apache Arrow

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

Change "Apache Arrow in Spark" to "Apache Arrow in PySpark"
and the link to “/sql-pyspark-pandas-with-arrow.html#apache-arrow-in-pyspark”

### Why are the changes needed?
When I click on the menu item it doesn't point to the correct page, and from the parent menu I can infer that the correct menu item name and link should be "Apache Arrow in PySpark".
like this:
 image
![image](https://user-images.githubusercontent.com/28332082/99954725-2b64e200-2dbe-11eb-9576-cf6a3d758980.png)

### Does this PR introduce any user-facing change?
Yes, clicking on the menu item will take you to the correct guide page

### How was this patch tested?
Manually build the doc. This can be verified as below:

cd docs
SKIP_API=1 jekyll build
open _site/sql-pyspark-pandas-with-arrow.html

Closes #30466 from liucht-inspur/master.

Authored-by: liucht <liucht@inspur.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>

docs/_data/menu-sql.yaml

@@ -64,17 +64,6 @@
       url: sql-distributed-sql-engine.html#running-the-spark-sql-cli
 - text: PySpark Usage Guide for Pandas with Apache Arrow
   url: sql-pyspark-pandas-with-arrow.html
-  subitems:
-    - text: Apache Arrow in Spark
-      url: sql-pyspark-pandas-with-arrow.html#apache-arrow-in-spark
-    - text: "Enabling for Conversion to/from Pandas"
-      url: sql-pyspark-pandas-with-arrow.html#enabling-for-conversion-tofrom-pandas
-    - text: "Pandas UDFs (a.k.a. Vectorized UDFs)"
-      url: sql-pyspark-pandas-with-arrow.html#pandas-udfs-aka-vectorized-udfs
-    - text: "Pandas Function APIs"
-      url: sql-pyspark-pandas-with-arrow.html#pandas-function-apis
-    - text: Usage Notes
-      url: sql-pyspark-pandas-with-arrow.html#usage-notes
 - text: Migration Guide
   url: sql-migration-old.html
 - text: SQL Reference