Offer a more generic `quarto_extract` or `extract_code` ?

[cderv]

Thanks for the links, loads of rich content in there, e.g. the first code chunk in the last link is as follows:

quarto inspect index.qmd | jq '
  .fileInformation[].codeCells |
  map(
    .metadata = (.metadata | to_entries | map("#| \(.key): \(.value)") | join("\n"))
  ) |
  group_by(.language) |
  map({
    language: .[0].language,
    contents: map(.metadata + "\n" + .source) | join("\n")
  })
'

I wonder if the same job could be achieved with a shorter incantation at some point e.g.

quarto extract --language=Python index.qmd

Originally posted by @Robinlovelace in #389

Related to #208 which is about R code cell