fix(webpack): give reveal.js's marked.js a 'exports' variable

I really don't know why this breaks only in a production build, but this
 evil
 hack makes the script work again.

 Closes https://github.com/hedgedoc/hedgedoc/issues/3862

Signed-off-by: David Mehren <git@herrmehren.de>

public/docs/release-notes.md

@@ -12,6 +12,7 @@ You now need Node 16 to run HedgeDoc. We don't support more recent versions of N
 
 ### Bugfixes
 - Fix that permission errors can break existing connections to a note, causing inconsistent note content and changes not being saved
+- Fix speaker notes not showing up in the presentation view
 
 ## <i class="fa fa-tag"></i> 1.9.7 <i class="fa fa-calendar-o"></i> 2023-02-19