Allow page alias to be an explicit URL pathname
In addition to a page ID, allow the value of a page alias to be an explicit URL pathname. The value must begin with a forward slash (e.g., /path/). For example:
This enhancement satisfies the use case of defining a vanity URL for a page. The vanity URL does not have to be expressed using the coordinate system and is therefore not constrained to its structure.
When the value of an alias begins with a forward slash, Antora still creates an alias entry in the content catalog. However, the value is assigned directly to the
pub.url property on the content file instead of that property being computed. Antora sets the
out.path on the content file so the site responds to the URL when the static redirect facility is in use.