12c: the block directive forms read and spell !adf: openers and closers

src/markdown/emit/block-directive-spelling.ts

@@ -1,12 +1,12 @@
 import type { AdfNode } from '../../adf/document.ts'
 import type { BlockDirective } from '../../adf/block-directives.ts'
 import { blockArgument } from '../block-directive-arguments.ts'
-import { isBareToken, spellAttributes, spellJsonAttribute, spellVocabulary } from '../directive-syntax.ts'
+import { directivePrefix, isBareToken, spellAttributes, spellJsonAttribute, spellVocabulary } from '../directive-syntax.ts'
 import { markValues, marksAttribute } from '../block-directive-marks.ts'
 import { nodeAttrs, nodeMarks } from '../../adf/document.ts'
 import { vocabularyPairs } from '../../adf/attribute-vocabulary.ts'
 
-export function spellDirectiveHeader(node: AdfNode, directive: BlockDirective, spelledByBody: readonly string[] = []): string | undefined {
+export function spellBlockDirectiveOpener(node: AdfNode, directive: BlockDirective, spelledByBody: readonly string[] = []): string | undefined {
   const argumentAttribute = blockArgument(node.type)
   const argument = spellArgument(node, argumentAttribute)
   if (argument === undefined) return undefined
@@ -17,7 +17,7 @@ export function spellDirectiveHeader(node: AdfNode, directive: BlockDirective, s
   const marks = nodeMarks(node)
   if (marks.length > 0) spelledPairs.push([marksAttribute, spellJsonAttribute(markValues(marks))])
   const attributes = spellAttributes(spelledPairs)
-  return `${node.type}${argument}${attributes === '' ? '' : ` ${attributes}`}`
+  return `${directivePrefix}${node.type}${argument}${attributes === '' ? '' : ` ${attributes}`}`
 }
 
 function spellArgument(node: AdfNode, argumentAttribute: string | undefined): string | undefined {