Updating the ExecutorGc heuristic help page and mentioning the wiki link

Author: ShubhamGupta29

app/views/help/spark/helpExecutorGcHeuristic.scala.html

@@ -17,4 +17,7 @@
 <p>This analysis shows how much time a job is spending in GC. To normalise the results across all jobs, the ratio of the time a job spends in Gc to the total run time of the job is calculated. </p>
 <p>A job is flagged if the ratio is too high, meaning the job spends too much time in GC.</p>
 <h3>Suggestions</h3>
-<p>We recommend increasing the executor memory.</p>
+<p>We recommend increasing the executor memory.</p>
+<p>Enabling ParallelGC using spark.executor.extraJavaOptions could help.</p>
+<p>Also recommended to reduce the number of UDF calls.</p>
+<p>For more help refer <a href="https://iwww.corp.linkedin.com/wiki/cf/display/DWH/Big+Data+Engineering+-+Advanced+Spark+SQL+Tuning+Techniques#BigDataEngineering-AdvancedSparkSQLTuningTechniques-GCtuning" target="_blank">here</a></p>