test: Avoid F541 (f-string without any placeholders)

test/functional/wallet_fast_rescan.py

@@ -49,7 +49,7 @@ class WalletFastRescanTest(BitcoinTestFramework):
         assert_equal(len(descriptors), NUM_DESCRIPTORS)
         w.backupwallet(WALLET_BACKUP_FILENAME)
 
-        self.log.info(f"Create txs sending to end range address of each descriptor, triggering top-ups")
+        self.log.info("Create txs sending to end range address of each descriptor, triggering top-ups")
         for i in range(NUM_BLOCKS):
             self.log.info(f"Block {i+1}/{NUM_BLOCKS}")
             for desc_info in w.listdescriptors()['descriptors']: