Fix the false claims round one found, and refuse the content a code span dropped

src/markdown-inline.ts

@@ -48,7 +48,7 @@ export function tryImageLine(alt: string | undefined, href: string, path: Conver
   return attempt.ok ? attempt.value.line : undefined
 }
 
-// A demand names a run no spelling holds, and a carried node joins no run, so every pass carries one more node.
+// A demand names a run no spelling holds, and a carried node joins no run, so every pass carries at least one more node.
 function emitLine(nodes: readonly AdfNode[], container: LineContainer, path: ConvertErrorPath): Result<EmittedLine> {
   const carried = new Set<number>()
   for (;;) {
@@ -262,6 +262,7 @@ function emitCodeSpan(nodes: readonly AdfNode[], depth: number, range: NodeRange
   for (const node of nodes) {
     if (node.type !== 'text' || (node.marks ?? []).length !== depth + 1) return success({ carry: range })
     if (typeof node.text !== 'string' || node.text === '') return failure('unsupported-node-shape', 'a text node holds text', path)
+    if ((node.content ?? []).length > 0) return failure('unsupported-node-shape', 'a text node holds no content', path)
     text += node.text
   }
   if (/[\n\r]/.test(text)) return success({ carry: range })