feat(todoist): add 3rd party fallback completion loader

https://github.com/sachaos/todoist

Notably, current version of todoist uses github.com/urfave/cli/v2, but
loading the completion appears to work with the "v1" loader we have
just fine.

Author: scop

completions/.gitignore

@@ -316,6 +316,7 @@
 /_tkn
 /_tkn-pac
 /tightvncviewer
+/_todoist
 /_tofu
 /tracepath6
 /_trivy

completions/Makefile.am

@@ -896,6 +896,7 @@ CLEANFILES = \
 	_tkn \
 	_tkn-pac \
 	tightvncviewer \
+	_todoist \
 	_tofu \
 	tracepath6 \
 	_trivy \
@@ -1216,7 +1217,7 @@ endif
 	$(ss) sha256sum \
 		b2sum md5sum shasum sha1sum sha224sum sha384sum sha512sum
 	$(ss) _sops \
-		_kata-runtime
+		_kata-runtime _todoist
 	$(ss) ssh \
 		autossh scp sftp sidedoor slogin
 	$(ss) sudo \