Log if peer actually uses unusual feerate

[rustyrussell]

          > https://fedorapeople.org/~wtogami/a/2023/0001-DO-NOT-COMMIT-Temporary-workaround-for-LND-update_fe.patch Temporary workaround for v23.05.2

Your setchannel approach of runtime switchable ignore fees is far superior to temporary hack that requires restarting CLN.

Would it be possible to add a print to let you know every time an ignore fee event happened?

What I like about my ugly hack is the print tells you exactly what is happening. It is diagnostically useful to know because it should happen JUST ONCE per channel to recover from LND's bug after their fee estimator was broken in the past. If it happens more than once the remote peer's fee estimator is currently broken. You want to know that so there is a chance to talk to the sysadmin to be able to fix it. It appears this PR currently would be silent when it ignores which is less informative?

This may be possible, but the current PR works by telling channeld an infinite allowable range. I think we can do logging in lightningd however, if the actual feerate used is weird.

I will do this as a separate PR.

Originally posted by @rustyrussell in #6398 (comment)