Answer prose round 1: the refusal list lives in the error row, the slot rule gives its reason, and stale item citations go

CHANGELOG.md

@@ -18,11 +18,12 @@
   spelled `-0`, and a `codeBlock` of several text nodes is a fence per node. A `codeBlock` holding
   other than plain text nodes rides the block carry, where it was refused.
 - **Breaking:** `unspellable-character` and `unspellable-line-start` leave `ConvertErrorCode`, and
-  `adfToMarkdown` no longer refuses `unspellable-whitespace`. A carriage return in text is spelled
+  `adfToMarkdown` no longer returns `unspellable-whitespace`. A carriage return in text is spelled
   `
` and a null character `!adf:text{text="\u0000"}`; a paragraph line opening with a code span
-  is spelled as one, its backticks opening no fence; a code block holding either character, a text
-  node holding no text or holding `content`, and an `emoji`, `mention` or `status` whose `text` holds
-  a line ending or a null character ride the carry. See `MIGRATION.md`.
+  is spelled as that code span, its backticks opening no fence; a code block holding either
+  character, a code span holding a null character, a text node holding no text or holding
+  `content`, and an `emoji`, `mention` or `status` whose `text` holds a line ending or a null
+  character ride the carry. See `MIGRATION.md`.
 - Fix a link `title` holding a null character: it is written as `!adf:link[text]{attrs}`, where it
   read back as U+FFFD.
 - **Breaking:** `unspellable-link` leaves `ConvertErrorCode`; a link whose `href` or `title` no