Merge pull request #13997 from MaryNfs/remove_eth_coinbase

Removed deprecated eth_coinbase from json-rpc docs[#13996]

Author: wackerow

public/content/developers/docs/apis/json-rpc/index.md

@@ -387,6 +387,8 @@ curl -X POST --data '{"jsonrpc":"2.0","method":"eth_syncing","params":[],"id":1}
 
 Returns the client coinbase address.
 
+> **Note:** This method has been deprecated as of **v1.14.0** and is no longer supported. Attempting to use this method will result in a "Method not supported" error.
+
 **Parameters**
 
 None
@@ -1671,10 +1673,10 @@ geth --http --dev console 2>>geth.log
 
 This will start the HTTP RPC interface on `http://localhost:8545`.
 
-We can verify that the interface is running by retrieving the Coinbase address and balance using [curl](https://curl.se). Please note that data in these examples will differ on your local node. If you want to try these commands, replace the request params in the second curl request with the result returned from the first.
+We can verify that the interface is running by retrieving the coinbase address (by obtaining the first address from the array of accounts) and balance using [curl](https://curl.se). Please note that data in these examples will differ on your local node. If you want to try these commands, replace the request params in the second curl request with the result returned from the first.
 
 ```bash
-curl --data '{"jsonrpc":"2.0","method":"eth_coinbase", "id":1}' -H "Content-Type: application/json" localhost:8545
+curl --data '{"jsonrpc":"2.0","method":"eth_accounts","params":[]", "id":1}' -H "Content-Type: application/json" localhost:8545
 {"id":1,"jsonrpc":"2.0","result":["0x9b1d35635cc34752ca54713bb99d38614f63c955"]}
 
 curl --data '{"jsonrpc":"2.0","method":"eth_getBalance", "params": ["0x9b1d35635cc34752ca54713bb99d38614f63c955", "latest"], "id":2}' -H "Content-Type: application/json" localhost:8545