doc: fix/improve analyzepsbt in doc/psbt.md
doc: fix/improve analyzepsbt in doc/psbt.md

- fix: replace "RPC" with "PSBT"

- output includes the current status of the analyzed psbt's inputs

- apply "if possible" to the fee as well as to the estimated weight and feerate, since the fee is only shown if all utxo slots in the psbt have been filled

- add "final" to the estimated weight and feerate

DigitalPandacoin/pandacoin,peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,DigitalPandacoin/pandacoin,peercoin/peercoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,peercoin/peercoin