docs: correct the stale cross-feature edge comment (RD-03 follow-up)

RD-03 added `overzicht: ['registratie']`, so the comment claiming
`herregistratie: ['registratie']` is "the one sanctioned cross-feature
edge" became false. There are two, and both point at registratie.

State what each edge is for instead of counting them, so the next
context added does not make the comment wrong again.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.dependency-cruiser.ssp.js

@@ -2,10 +2,13 @@
 // scaffolding one (see `gen:context`, WP-44).
 module.exports = require('./.dependency-cruiser.base.js')(
   {
+    // Two sanctioned cross-feature edges, both pointing at registratie: the portal home
+    // composes registratie's dashboard sections (RD-03), and herregistratie builds on a
+    // registration. Every other context imports only libs/shared and libs/beheer.
     overzicht: ['registratie'],
     auth: [],
     registratie: [],
-    herregistratie: ['registratie'], // the one sanctioned cross-feature edge
+    herregistratie: ['registratie'],
     brief: [],
     showcase: null, // unrestricted — the sanctioned teaching page; nothing imports it
   },