Add `raw_markdown` extension affecting `ipynb` reader.

Specifying `-f ipynb+raw_markdown` will cause Markdown cells
to be represented as raw Markdown blocks, instead of being
parsed.  This is not what you want when going from `ipynb`
to other formats, but it may be useful when going from `ipynb`
to Markdown or to `ipynb`, to avoid semantically insignificant
changes in the contents of the Markdown cells that might
otherwise be introduced.

Closes #5408.

0 files changed, 0 insertions, 0 deletions