Need a friendlier network name for the user manual

Whilst pointing to shadow is nice, it would be good to have a name to use that can be used either internally or externally to point to the manual on shadow without giving away the server name to the whole world easily. This could be used on the external website then as well as 'internally' (e.g. for links from the client), and would persist if we ever change the server hosting the information without having to set up extra links at that point. (Changes to the external web had stalled waiting for this, and after suggestions of adding help links in the client it seemed like adding this as a ticket would be a good idea, before we have too much that could need changing.)

The issue refers to the manual on shadow, the external website, and links from the client, but names no file, test, or entry point. First clarify where the manual URL is currently defined and whether the friendly name requires repository changes or external infrastructure. Done means the manual has a stable, non-server-revealing name usable by both the website and client links.

Scritto dal modello di indicizzazione a partire dal testo della issue.