Normal whitespace is not significant, so you cannot create a link containing only whitespace. You'll have to use something like the no-break space (NBSP).
Using the wiki link markup ([[]]):
[["\u00A0\u00A0"|Hidden Passage]]
Using the <a> tag with the data-passage attribute:
Comments
Using the wiki link markup (
[[]]
): Using the<a>
tag with thedata-passage
attribute: