Weird markdown dash list rendering

[andreasabel]

Blocked by:

• gfmExtensions parser drops out of list when | is encountered jgm/commonmark-hs#95

Issue description:

Compare the first and second dash list. This is the source:

### 1.3.2

_2022-07-18, Andreas Abel_

- Export `Text.Regex.TDFA.Pattern.decode{PatternSet|CharacterClass}`
  ([#16](https://github.com/haskell-hvr/regex-tdfa/issues/16))
- Extend and correct docs for 'Pattern' module
- Tested with GHC 7.4 - 9.4

### 1.3.1.5

_2022-07-18, Andreas Abel_

- Allow dash (`-`) as start of a range, e.g. `[--z]`
  ([#1](https://github.com/haskell-hvr/regex-tdfa/issues/1),
  [#45](https://github.com/haskell-hvr/regex-tdfa/pull/45))
- Tested with GHC 7.4 - 9.4

Could be an upstream issue in commonmark, need to test there.
UPDATE: At least the vanilla commonmark parser treats this correctly.

[andreasabel]

I can reproduce the issue with the combination commonmarkWith (mathSpec <> gfmExtensions <> defaultSyntaxSpec) that we currently use in hackage-server:

hackage-server/src/Distribution/Server/Util/Markdown.hs

Line 164 in ae4f14e

runIdentity (commonmarkWith (mathSpec <> gfmExtensions <> defaultSyntaxSpec)

Minimal reproducer:

{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE ScopedTypeVariables #-}

import Commonmark
import Commonmark.Extensions

import Data.String.QQ (s)
import Data.Text.Lazy.IO as TLIO

main :: IO ()
main = do
  commonmarkWith (gfmExtensions <> defaultSyntaxSpec) "inline" input >>= \case
    Left e                  -> error (show e)
    Right (html :: Html ()) -> TLIO.putStr $ renderHtml html
  where
  input = [s|
- foo
- `a|b`
- bar
|]

{- Produces:

<ul>
<li>foo
</li>
</ul>
<p>- <code>a|b</code></p>
<ul>
<li>bar
</li>
</ul>

Seems like the gfmExtensions parser cannot deal with `|`.
-}