Revert "Prepend jupyter_ to jupyter metadata keys."

This reverts commit 5eaff399d5.

src/Text/Pandoc/Readers/Ipynb.hs

@@ -72,14 +72,8 @@ notebookToPandoc :: (PandocMonad m, FromJSON (Notebook a))
 notebookToPandoc opts notebook = do
   let cells = notebookCells notebook
   let (fmt,fmtminor) = notebookFormat notebook
-  let jupyterMetaFields :: [String]
-      jupyterMetaFields = ["kernelspec", "language_info", "toc"]
   let m = M.insert "nbformat" (MetaString $ show fmt) $
           M.insert "nbformat_minor" (MetaString $ show fmtminor) $
-          -- mark jupyter fields specially so it doesn't trigger toc
-           M.mapKeys (\k -> if k `elem` jupyterMetaFields
-                              then "jupyter_" <> k
-                              else k) $
           jsonMetaToMeta (notebookMetadata notebook)
   let lang = case M.lookup "kernelspec" m of
                    Just (MetaMap ks) ->

src/Text/Pandoc/Writers/Ipynb.hs

@@ -38,7 +38,6 @@ import Prelude
 import Control.Monad.State
 import qualified Data.Map as M
 import Data.Maybe (catMaybes, fromMaybe)
-import Data.List (isPrefixOf)
 import Text.Pandoc.Options
 import Text.Pandoc.Definition
 import Data.Ipynb as Ipynb
@@ -79,11 +78,6 @@ pandocToNotebook opts (Pandoc meta blocks) = do
   let inlineWriter ils = T.stripEnd <$> writeMarkdown
            opts{ writerTemplate = Nothing } (Pandoc nullMeta [Plain ils])
   metadata' <- metaToJSON' blockWriter inlineWriter $
-                 (Meta .
-                  M.mapKeys (\k -> if "jupyter_" `isPrefixOf` k
-                                      then drop 8 k
-                                      else k) .
-                  unMeta) $
                  B.deleteMeta "nbformat" $
                  B.deleteMeta "nbformat_minor" $ meta
   let metadata = case fromJSON metadata' of