Answer product-owner round 1: name the cycle in its own message and in the error table

CHANGELOG.md

@@ -31,8 +31,9 @@
   `collection`, `id` and `occurrenceKey` directly where they rode the opaque carry.
 - Fix an image inside another image's description: it flattens into the alt text, where it was
   refused.
-- Fix a document holding itself, through a node's `content` or an attribute: `adfToMarkdown`,
-  `adfToPlainMarkdown` and `isAdfDocument` refuse it as `not-an-adf-document`, where they hung.
+- Fix a cyclic document, in which a node or an attribute value holds itself: `adfToMarkdown` and
+  `adfToPlainMarkdown` refuse it as `not-an-adf-document` and `isAdfDocument` returns `false`,
+  where all three hung.
 
 ## 0.1.0