Record deep equality, the text break, empty keys, -0, the typed carry fence and per-node code fences; file items 52 and 53

CHANGELOG.md

@@ -2,10 +2,20 @@
 
 ## Unreleased
 
-- **Breaking:** directives, the opaque carry among them (now `carry`), are spelled under an `!adf:`
-  prefix (`!adf:name … !adf:/name`, `!adf:name[content]{attrs}`, `!adf:name arg {attrs}`) in place
-  of the `:::`/`::`/`:name` forms: text holding an unescaped `!adf:` is claimed, and `adf` is an
-  ordinary code block language. Convert stored markdown per `MIGRATION.md`.
+- **Breaking:** directives, the inline opaque carry among them (now `!adf:carry{json="…"}`), are
+  spelled under an `!adf:` prefix (`!adf:name … !adf:/name`, `!adf:name[content]{attrs}`,
+  `!adf:name arg {attrs}`) in place of the `:::`/`::`/`:name` forms, and the block carry is a code
+  fence whose info string `adf:<type>` names the node's type, its body the node's JSON without
+  `type`: text holding an unescaped `!adf:` and a code fence whose info string opens `adf:` are
+  claimed, and `adf` is an ordinary code block language. Convert stored markdown per `MIGRATION.md`.
+- **Breaking:** `markdownToAdf` reads markdown holding no block as a document whose `content` is
+  empty, as Atlassian's schema requires; `!adf:doc {content=none}` spells a document holding no
+  `content` key.
+- `markdownToAdf(adfToMarkdown(doc))` deep-equals `doc`: two adjacent text nodes a reader would
+  join are parted by `!adf:textBreak{}`, an empty `attrs`, `content` or `marks` is spelled
+  `{attrs=empty}`, `{content=empty}` or `{marks=empty}`, `-0` is 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-link` leaves `ConvertErrorCode`; a link whose `href` or `title` no
   CommonMark escape spells is written as `!adf:link[text]{attrs}`.
 - **Breaking:** some directive refusals carry `malformed-directive` where they carried