The .txt extensions were changed to .adoc in 1f010d6bdf (doc: use .adoc extension for AsciiDoc files, 2025-01-20). Do the same for contrib/subtree. Signed-off-by: Todd Zullinger <tmz@pobox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1f010d6bdf