Update include.md

[luigir-it]

include:template directive should use an include template, not a pre-built configuration file (configuration template)

[rcdailey]

Thank you very much for the PR. Please know that the YAML snippets in the reference documentation are not intended to be "functional" or kept in sync with the configuration templates repository. The purpose of the snippets is to show users the overall YAML schema (structure) so that they know how to use it. For that reason, I will close this PR without merging. I'm sorry for the wasted effort. In the future, I recommend opening a discussion or issue before doing work.

[luigir-it]

Don't worry, I did very little. But since that example may create misunderstandings, I thought it was worth fixing it.
If the problem is "keeping in sync" with the wiki, than you can put a placeholder there, like "include_template", instead of something that may create confusion.