Citing a node only by its sid

Wherever a node is cited, a rule, a term or a node of a project's own kind, it is cited by its sid, never by its location (§s-kag2m9tzdnduxdx). sheriff binding holds every file of the repository to this but those under specs/, where sheriff validate checks the citations in the nodes (§s-qzyacnqwvaeaps4).

• A location of a node found in a file is refused, in any case of its letters and whether or not the node exists now.
• One exception: the fixtures of the tests of a check that reads citations or locations. Such a test needs a file holding a location, as the data it feeds the check. The files are those the project's own guidelines list as fixtures (§s-6hha5en226aj8hu).