markdown-include is GPL licensed.
Also, rewrite it as a block processor, so that it works correctly
inside indented blocks.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This commit re-adds the integration for canarytokens.org, now separate
from the primary Thinkst integration.
Signed-off-by: David Wood <david@davidtw.co>