Clarify if OKF links require URL encoding

In § 5 it is stated that _"Concepts MAY link to other concepts using standard markdown links."_ Two forms are supported, absolute or relative links.

However, in typical Markdown it is not standardized if that path should be URL encoded or not. In Obsidian, that path MUST be URL encoded, so a markdown link for `[[Open Knowledge Format]]` must be [Open Knowledge Format](/Open%20Knowledge%20Format.md).

On the other hand, another common Markdown tool [Hugo](https://gohugo.io/) does NOT require url encoding paths.

Should OKF require it, not require it, or is taking a stance on this not necessary?

Start with § 5 of the OKF specification and compare the linked Obsidian and Hugo behaviors described in the issue. Clarify whether relative Markdown links require URL encoding, forbid it, or leave it implementation-dependent; done means the specification states the decision unambiguously.

Written by the indexing model from the issue text.