Previously, the "payment" and "invoice" paths were completely separate, but this now calls both. It bypasses htlc_sets (and thus, cannot do MPP), and bypasses the hook too: the former is tied closely to HTLCs, and the hook is also very htlc-centric.
Includes finishing unfinished sentence in sendpay man page, as a bonus.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: Plugins: `sendpay` now allows self-payment of invoices, by specifying an empty route.