jgm/pandoc: pandoc 2.9.1.1

Markdown reader:

• Fix parsing bug affected indented code after raw HTML (#6009, #5360).

LaTeX writer:

• Fix regression in beamer slide structure with certain slide levels (#6030).
• Allow framebreaks for beamer's TOC (Heiko Schlittermann, #6012)
• Properly handle unnumbered headings level 4+ (#6018). Previously the \paragraph command was used instead of \paragraph* for unnumbered level 4 headings.

HTML writer:

• Fix revealjs slide structure regression with certain slide levels (#6030).
• Add newlines to make slide show output more readable.

Org writer:

• Remove extra spaces from table cells (Albert Krewinkel, #6024).

JATS template: Update JATS dtd (Arfon Smith, #6020). Use the archiving and interchange DTD rather than the more restrictive journal publishing DTD (which doesn't permit ext-link as a valid child).

Text.Pandoc.PDF: Fix runTeXProgram so that the input source is always overwritten (#6027). Previously it wasn't overridden if the file already existed, which led to bad results on subsequent runs when pdf-engine-opt=-output-directory= was used to specify an explicit temp dir.

Text.Pandoc.BCP47: Change getLang to handle block-level contents (#6008). Some readers (e.g. RST) will populate the lang metadata field with block-level content. getLang has been modified to handle this. Previously in these cases the LaTeX writer would not properly set the "main language" of the document.

Fix test/tables.org (Albert Krewinkel).

Use HTTPS in copyright message (Felix Yan, #6010)