Mismatch between selected and detected feerate

[pythcoiner]

While i was testing #563, found out that the detected feerate (5405sats/vb here) mismatch w/ user feerate (5001 sats/vb here):

[darosior]

That's most likely because of the not-created change output. We should warn the user in this case (see #811). I don't think there is anything to be done here, please let me know if you disagree.

[pythcoiner]

it's fine with me, just want to notice it in case it can let room for error w/ fee calculations