second attempt at placing a youtube video on our docs index
second attempt at placing a youtube video on our docs index

(followup to PR #2799)

googlefonts/fontbakery,moyogo/fontbakery,graphicore/fontbakery,moyogo/fontbakery,moyogo/fontbakery,googlefonts/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,graphicore/fontbakery