wallet/transaction/edit - Edits an existing transaction.

Method parameters:
id - The ID of the transaction to edit.
amount - The new amount of the transaction.
description - The new description of the transaction.

Returns a JSON document of the following format:
<boolean> - Always true.

Expected errors:
TRANSACTION_NOT_FOUND - A transaction with the ID doesn't exist.
ENTER_AMOUNT - The new amount is zero.