one <button> closing out of place

[pauloney]

There is exact ONE closing out of place in program.html.

<a class="pdfLink" href="assets/pdf/Oleksandr-Baranovskyi-TUG2022-preprint.pdf"><img src="assets/img/PDF_24.png" alt="Preprint"/></a></button>

it should be on a new line following the indentation.