Update doc on how to write configuration files (#3690)
Update doc on how to write configuration files (#3690)

* Update doc on how to write the configuration file

* Addressing PR suggestions

DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core