docs: update sample-tapd.confg for psbt-max-fee-ratio

Author: GeorgeTsagk

sample-tapd.conf

@@ -396,6 +396,10 @@
 ; the syncer cache. (default: 10240)
 ; universe.multiverse-caches.root-node-page-cache-size=10240
 
+[wallet]
+; The maximum ratio of fees to total output amount for the wallet funded PSBTs.
+; Value must be a valid float ranging from 0.00 to 1.00.
+; wallet.psbt-max-fee-ratio=0.75
 
 [address]