Replace */tasks commands w/ magit-todos-list

If we want ivy/helm interfaces to it, we should use magit-todos as a
backend.

modules/completion/helm/autoload/helm.el

@@ -1,11 +1,5 @@
 ;;; completion/helm/autoload/helm.el -*- lexical-binding: t; -*-
 
-;;;###autoload
-(defun +helm/tasks (&optional _arg)
-  (interactive "P")
-  ;; TODO Implement `+helm/tasks'
-  (error "Not implemented yet"))
-
 ;;;###autoload
 (defun +helm/projectile-find-file ()
   "Call `helm-find-files' if called from HOME, otherwise