`preamble-discussions-to`

The discussions-to header is a valid URL.

Examples

error[preamble-discussions-to]: preamble header `discussions-to` is not a valid URL
 --> input.md:6:16
  |
6 | discussions-to: not a website dot com
  |                ^^^^^^^^^^^^^^^^^^^^^^ relative URL without a base
  |

Explanation

preamble-discussions-to makes sure that the discussions-to front matter (or preamble) header is a correctly formatted URL.