Commits
Nic Crane authored and Jonathan Keane committed 670af338bc7
ARROW-15022: [R] install vignette and installation dev vignette need alt text for images Closes #11972 from thisisnic/ARROW-15022_alt_text Authored-by: Nic Crane <thisisnic@gmail.com> Signed-off-by: Jonathan Keane <jkeane@gmail.com>