Suggest config.rb instead of knife.rb

[ghost]

As seen in documentation here, it is mentioned that:

The config.rb file is a replacement for the knife.rb file, starting with the chef-client 12.0 release. The config.rb file has identical settings and behavior to the knife.rb file. The chef-client will first look for the presence of the config.rb file and if it is not found, will look for the knife.rb file.

Therefore, maybe it would be more appropriate to suggest adding the local config to config.rb instead of knife.rb.