a7526b6a70 Remove `fee_vb` (yancy)
73b14d03b9 Add `to_fee` in place of `fee_wu` (yancy)
Pull request description:
Rename fee_wu and remove fee_vb
closes https://github.com/rust-bitcoin/rust-bitcoin/issues/3908
ACKs for top commit:
apoelstra:
ACK a7526b6a70642e04f0a8ad8a89aa368031fdb6cd; successfully ran local tests
Kixunil:
ACK a7526b6a70
Tree-SHA512: fd865525e56caddc49158fd94fb125d92fd09654d5c72609a6f8e34370e79a9be4213dbd7e69b0d8498d92fca8a970142262f56b63cebd76c200aca75b6e0ca6