fix(mdxish): honor backslash escaped list and hash markers in JSX table cells

[maximilianfalco]

🎫 Resolve RM-16838

🎯 What does this PR do?

Two fixes inside <table> and <Table> cells in mdxish-tables.ts:

1. Honor single-backslash escapes for block markers

\-, \*, \+, \# now render as literal text. Previously you needed two backslashes.

Why it was broken: mdxish-tables.ts double-parses cell content. The first pass (outer mdxjs) consumes the \ correctly per CommonMark, leaving the resolved marker as text. The second pass (processTableNode's re-parse for gemoji / variables / bold / etc.) sees the bare marker at the start of a fresh document and re-tokenises it as a list / heading.

Fix: before the second parse, peek at the cell's original source. If it started with \-/\*/\+/\#, re-prepend the \ so the inner parser honors the escape the same way the outer one did.

2. Flatten standalone block markers to literal text

A lone -/*/+/#/>/---/*** in a cell — common in header rows — used to render as an empty bullet list, empty heading, empty blockquote, or <hr>. Now it renders as the literal character.

Why it was broken: the inner re-parse takes any single character that could start a CommonMark block and tokenises it that way, even when there's no content after — producing <ul><li></li></ul> for <td>-</td> and similar nonsense for the other markers.

Fix: after the re-parse, if the result is a phantom empty block (empty list-item, empty heading, empty blockquote, thematic break), replace it with the user's original text. Blocks with real content (- foo, # heading, > quote) are untouched.

🧪 QA tips

Use this in the demo app

<table>
<thead><tr><th>#</th><th>-</th><th>-</th></tr></thead>
<tbody><tr><td>- fqefeq</td><td>- hello</td><td>-</td></tr></tbody>
</table>

<table>
<thead><tr><th>-</th><th>-</th><th>-</th></tr></thead>
<tbody><tr><td>- fqefeq</td><td>- hello</td><td>-</td></tr></tbody>
</table>

<Table>
  <thead>
    <tr><th>-</th><th>-</th><th>-</th></tr>
  </thead>
  <tbody>
    <tr><td>- fqefeq</td><td>- hello</td><td>-</td></tr>
  </tbody>
</Table>

| - | - |
| --- | --- |
| - fqefeq | - hello |
| - | - |

• previously you needed 2 backslashes to escape the - and #, now with the fix, you only need 1 which is the expected behaviour
• standalone - / # / > / --- cells render as literal text instead of empty bullets / headings / blockquotes / <hr>
• - foo / # heading / > quote still render as proper lists / headings / blockquotes (default markdown)

📸 Screenshot or Loom

Screen.Recording.2026-05-29.at.20.35.33.mov