[SPARK-33590][DOCS][SQL] Add missing sub-bullets in Spark SQL Guide

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

Add the missing sub-bullets in the left side of `Spark SQL Guide`

### Why are the changes needed?

The three sub-bullets in the left side is not consistent with the contents (five bullets) in the right side.

![image](https://user-images.githubusercontent.com/1315079/100546388-7a21e880-32a4-11eb-922d-62a52f4f9f9b.png)

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

Yes, you can see more lines in the left menu.

### How was this patch tested?

Manually build the doc as follows. This can be verified as attached:

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

![image](https://user-images.githubusercontent.com/1315079/100546399-8ad25e80-32a4-11eb-80ac-44af0aebc717.png)

Closes #30537 from kiszk/SPARK-33590.

Authored-by: Kazuaki Ishizaki <ishizaki@jp.ibm.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>

docs/_data/menu-sql.yaml

@@ -51,6 +51,10 @@
       url: sql-performance-tuning.html#other-configuration-options
     - text: Join Strategy Hints for SQL Queries
       url: sql-performance-tuning.html#join-strategy-hints-for-sql-queries
+    - text: Coalesce Hints for SQL Queries
+      url: sql-performance-tuning.html#coalesce-hints-for-sql-queries
+    - text: Adaptive Query Execution
+      url: sql-performance-tuning.html#adaptive-query-execution
 - text: Distributed SQL Engine
   url: sql-distributed-sql-engine.html
   subitems: