revealjs - remove Lua fix as Pandoc solves the issue

revert #1053 (cd72d7c) while keeping the test now that it is fixed upstream (jgm/pandoc#8098)

Author: cderv

src/resources/filters/quarto-post/reveal.lua

@@ -18,9 +18,6 @@ function reveal()
         Span = applyPosition,
         Image = applyPosition
       },
-      {
-        Div = fencedDivFix
-      }
     }
   else
     return {}
@@ -54,17 +51,4 @@ function asCssSize(size)
   else
     return size
   end
-end
-
-function fencedDivFix(el)
-  -- to solve https://github.com/quarto-dev/quarto-cli/issues/976
-  -- until Pandoc may deal with it https://github.com/jgm/pandoc/issues/8098
-  if el.content[1] and el.content[1].t == "Header" and el.attr.classes:includes("fragment") then
-    level = PANDOC_WRITER_OPTIONS.slide_level
-    if level and el.content[1].level > level then
-      -- This will prevent Pandoc to create a <section>
-      el.content:insert(1, pandoc.RawBlock("html", "<!-- -->"))
-    end
-  end
-  return el
 end