Fix approval docs

Author: Adam Majmudar

thirdweb/core/classes/erc_1155.py

@@ -318,7 +318,7 @@ def set_approval_for_all(self, operator: str, approved: bool) -> TxReceipt:
 
         ```python
         operator = "{{wallet_address}}"
-        approved = "0x..."
+        approved = true
 
         receipt = contract.erc1155.set_approval_for_all(operator, approved)
         ```

thirdweb/core/classes/erc_721.py

@@ -367,7 +367,7 @@ def set_approval_for_all(self, operator: str, approved: bool) -> TxReceipt:
 
         ```python
         operator = "{{wallet_address}}"
-        approved = "0x..."
+        approved = true
 
         receipt = contract.erc721.set_approval_for_all(operator, approved)
         ```