Doc syntax fix.

Signed-off-by: Yury-Fridlyand <yury.fridlyand@improving.com>

Author: Yury-Fridlyand

DEVELOPER_GUIDE.rst

@@ -225,7 +225,7 @@ Most of the time you just need to run ./gradlew build which will make sure you p
    * - ./gradlew build
      - 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))
+     - Run PiTest mutation testing (see more info in `#1204 <https://github.com/opensearch-project/sql/pull/1204>`_)
 
 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"``.