In the first 29 lines of your configuration.yaml file, are there any !include statements? If there are then the error message’s “line 29, column 1” isn’t the 29th line in the file. It’s the 29th line after the YAML processor has expanded all other files referenced via !include statements. In other words, it’s unlikely it’s complaining about the Toon sensor.
What is the first !include statement in configuration.yaml? For example, if it’s including automations.yaml then that is the file you should inspect for syntax errors.