[Confluence] Executable Code Blocks don't pass languageValue to Writer

For an executable code chunk like

```{python}
#| label: tbl-planets
#| tbl-cap: Planets

from IPython.display import Markdown
from tabulate import tabulate
table = [["Sun",696000,1989100000],
         ["Earth",6371,5973.6],
         ["Moon",1737,73.5],
         ["Mars",3390,641.85]]
Markdown(tabulate(
  table, 
  headers=["Planet","R (km)", "mass (x 10^29 kg)"]
))
```

python is not passed to the Writer

function CodeBlockConfluence(codeValue, attributes)
  local languageValue = attributes and attributes.class or ''
  dump(attributes, 'attributes')
  dump(codeValue, 'codeValue')
  dump(languageValue, 'languageValue')

languageValue	markdown
attributes	[("id",""),("class","markdown cell-code")]

Meeting notes: If this is complex, we should delay to next milestone.

[cscheid]

@allenmanning let's pair on this, there should be a way to see those classes. They might be on a different div up the document.