Update replace_transaction and modify_transaction docs (#2058)

replace_transaction() and modify_transaction() were listed as returning strings, when in fact they return HexBytes.

* Added a full tx hash, and added arguments back to modify_tx docs

Co-authored-by: kclowes <kclowes@users.noreply.github.com>

Author: schwartzman

docs/web3.eth.rst

@@ -893,7 +893,7 @@ The following methods are available on the ``web3.eth`` namespace.
       and ``maxPriorityFeePerGas``. These will likely be default values and may result in an
       unsuccessful replacement of the pending transaction.
 
-    This method returns the transaction hash of the replacement transaction.
+    This method returns the transaction hash of the replacement transaction as a HexBytes object.
 
     .. code-block:: python
 
@@ -902,12 +902,13 @@ The following methods are available on the ``web3.eth`` namespace.
                 'from': web3.eth.coinbase,
                 'value': 1000
             })
-        '0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331'
+        HexBytes('0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331')
         >>> web3.eth.replace_transaction('0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331', {
                 'to': '0xd3CdA913deB6f67967B99D67aCDFa1712C293601',
                 'from': web3.eth.coinbase,
                 'value': 2000
             })
+        HexBytes('0x4177e670ec6431606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1528989')
 
 .. py:method:: Eth.replaceTransaction(transaction_hash, new_transaction)
 
@@ -927,7 +928,7 @@ The following methods are available on the ``web3.eth`` namespace.
 
     The same validation and defaulting rules of :meth:`~web3.eth.Eth.replace_transaction` apply.
 
-    This method returns the transaction hash of the newly modified transaction.
+    This method returns the transaction hash of the newly modified transaction as a HexBytes object.
 
     .. code-block:: python
 
@@ -936,9 +937,9 @@ The following methods are available on the ``web3.eth`` namespace.
                 'from': web3.eth.coinbase,
                 'value': 1000
             })
-        '0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331'
-        >>> web3.eth.modify_transaction
-        ('0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331', value=2000)
+        HexBytes('0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331')
+        >>> web3.eth.modify_transaction(('0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331', value=2000)
+        HexBytes('0xec6434e6701771606e55d6b4ca35a1a6b75ee3d73315145a921026d15299d05')
 
 .. py:method:: Eth.modifyTransaction(transaction_hash, **transaction_params)