Adding Spotless to DEVELOPER_GUIDE.rst

Signed-off-by: Mitchell Gale <[email protected]>

DEVELOPER_GUIDE.rst

@@ -113,7 +113,7 @@ Note that missing license header will be detected by Gradle license plugin and f
 Making Code Changes
 ===================
 
-Project Strucure
+Project Structure
 ----------------
 
 The plugin codebase is in standard layout of Gradle project::
@@ -224,6 +224,10 @@ Most of the time you just need to run ./gradlew build which will make sure you p
      - Build plugin by run all tasks above (this takes time).
    * - ./gradlew pitest
      - Run PiTest mutation testing (see more info in `#1204 <https://github.com/opensearch-project/sql/pull/1204>`_)
+   * - ./gradlew spotlessCheck
+     - Runs Spotless to check for code style.
+   * - ./gradlew spotlessApply
+     - Automatically apply spotless code style changes.
 
 For integration test, you can use ``-Dtests.class`` “UT full path” to run a task individually. For example ``./gradlew :integ-test:integTest -Dtests.class="*QueryIT"``.