Use delimiters for links with space in HyWiki

[matsl]

What

Use delimiters for links with space in HyWiki.

Why

Do no convert links containing dashes to space. Use links as they are
written just like org does. Publishing is thus close to what org
supports and close to how org links are written (without the org link
delimiters.).

Note

HyWiki links will thus be different from Hyperboles path links where
links can be given either as a delimited string with spaces or a
string where dashes represent space in the linked header. So old
behavior remains there.

Docstrings that mentions dash to space conversion has not been updated
yet. Will do that if we choose this solution.

[rswgnu]

Since I believe this works properly already outside of publishing and it is harder when typing a section reference to add delimiters around the reference than to type dashes, let's discuss and decide.