message: test: convert docs into type annotations in test_framework/wallet.py
diff: from decimal import Decimal
  from enum import Enum
  +from typing import Optional
  from test_framework.address import ADDRESS_BCRT1_P2WSH_OP_TRUE
  from test_framework.key import ECKey
  from test_framework.messages import (
  @@ -105,12 +106,12 @@ class MiniWallet:
  def get_address(self):
  return self._address
  - def get_utxo(self, *, txid='', mark_as_spent=True):
  + def get_utxo(self, *, txid: Optional[str]='', mark_as_spent=True):
  """
  Returns a utxo and marks it as spent (pops it from the internal list)
  Args:
  - txid (string), optional: get the first utxo we find from a specific transaction
  + txid: get the first utxo we find from a specific transaction
  Note: Can be used to get the change output immediately after a send_self_transfer
  """
  