[spec] relative link behavior definition

[Stephane Bortzmeyer]

On Tue, Mar 23, 2021 at 10:08:48AM +0100,
 Omar Polo <op at omarpolo.com> wrote 
 a message of 22 lines which said:

> [0] the URL rfc specifies a cleaning algorithm that removes every
>     .. path component with the preceding non-.. component.

This is RFC 3986
<gemini://gemini.bortzmeyer.org/rfc-mirror/rfc3986.txt>, and, indeed,
it is standard, it is not up to client's choice.