966666de9a doc: Remove wrong and redundant doxygen tag (MarcoFalke)
Pull request description:
`param@[in]` is not a valid doxygen tag. Also, no other function in this file uses the annotations, and they are redundant with the line above, so just remove them in `feerate` to fix all issues.
In other places, fix them.
ACKs for top commit:
cedwies:
ACK 966666d
janb84:
ACK 966666de9a
pablomartin4btc:
ACK 966666de9a
w0xlt:
ACK 966666de9a
Tree-SHA512: fcb6aa75c0f03b36f3caad023854ba276e0335cf47908a77006e182633b6a68f7b7d3115ef9fb97d143ca23730def05550f970265bb1fde97594ba68e724bde9