Update burns.sql

Enhanced Readme in the script to make it more clear

Author: uschwinn

data-platform/core-converged-db/resource-manager/scripts/burns.sql

@@ -1,4 +1,4 @@
--- Run the script to burn CPU
--- First execute burn.sql
+-- Connect to REDEF_USER and run the script to burn CPU
+-- First execute burn.sql to create the function and the required user
 
 SELECT redef_user.burn_cpu (5) FROM dual;