docs: Add instructions for running individual Spark SQL tests from sbt (#1752)

Author: coderfender

docs/source/contributor-guide/spark-sql-tests.md

@@ -54,7 +54,7 @@ git apply ../datafusion-comet/dev/diffs/3.4.3.diff
 
 ## 3. Run Spark SQL Tests
 
-Use the following commands to run the SQL tests locally.
+#### Use the following commands to run the Spark SQL test suite locally.
 
 ```shell
 ENABLE_COMET=true build/sbt catalyst/test
@@ -65,6 +65,15 @@ ENABLE_COMET=true build/sbt "hive/testOnly * -- -l org.apache.spark.tags.Extende
 ENABLE_COMET=true build/sbt "hive/testOnly * -- -n org.apache.spark.tags.ExtendedHiveTest"
 ENABLE_COMET=true build/sbt "hive/testOnly * -- -n org.apache.spark.tags.SlowHiveTest"
 ```
+#### Steps to run individual test suites
+1. Open SBT with Comet enabled
+```sbt
+ENABLE_COMET=true sbt -Dspark.test.includeSlowTests=true 
+```
+2. Run individual tests (Below code runs test named `SPARK-35568` in the `spark-sql` module)
+```sbt
+ sql/testOnly  org.apache.spark.sql.DynamicPartitionPruningV1SuiteAEOn -- -z "SPARK-35568"
+```
 
 ## Creating a diff file for a new Spark version