Executes the response body as a [template](/docs/modules/http.handlers.templates) document. Templates provide functional primitives for making simple dynamic pages. Features include HTTP subrequests, HTML file includes, Markdown rendering, JSON parsing, basic data structures, randomness, time, and more.
- **mime** are the MIME types the templates middleware will act on; any responses that do not have a qualifying Content-Type will not be evaluated as templates. Default: `text/html text/plain`.
- **between** are the opening and closing delimiters for template actions. Default: `{{printf "{{ }}"}}`. You can change them if they interfere with the rest of your document.
- **root** is the site root, when using functions that access the file system.
