caption-inline-variable

{{variable}} nodes are valid caption content — parsed as Variable, resolved by consumer

§6.2

Input

```python
x = 1
```
^ Version {{version}} — {{author}}

Output AST

- type: CodeBlock
  language: python
  raw: x = 1
  caption:
    - type: Text
      value: "Version "
    - type: Variable
      key: version
    - type: Text
      value: " — "
    - type: Variable
      key: author