Address comments

Author: sunchao

docs/sql-performance-tuning.md

@@ -119,7 +119,7 @@ that these options will be deprecated in future release as more optimizations ar
     <td>32</td>
     <td>
       Configures the threshold to enable parallel listing for job input paths. If the number of
-      input paths is larger than this threshold, Spark will use parallel listing on the driver side.
+      input paths is larger than this threshold, Spark will list the files by using Spark distributed job.
       Otherwise, it will fallback to sequential listing. This configuration is only effective when
       using file-based data sources such as Parquet, ORC and JSON.
     </td>

docs/tuning.md

@@ -264,7 +264,7 @@ parent RDD's number of partitions. You can pass the level of parallelism as a se
 or set the config property `spark.default.parallelism` to change the default.
 In general, we recommend 2-3 tasks per CPU core in your cluster.
 
-# Parallel Listing on Input Paths
+## Parallel Listing on Input Paths
 
 Sometimes you may also need to increase directory listing parallelism when job input has large number of directories,
 otherwise the process could take a very long time, especially when against object store like S3.