Cleans up the API: we have two functions now, one which is explicitly for
"I'm failing this because I saw this tx onchain".
Now we can correctly report the tx which closed the channel (previously
we would always report our own tx(s)!).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Fixed: JSON-RPC: `close` now correctly reports the txid of the remote onchain unilateral tx if it races with a peer close.
Changelog-Fixed: Protocol: we no longer try to spend anchors if a commitment tx is already mined (reported by @niftynei).
Fixes: #7526
5192eebef9