Update json-rpc.md

[rmoreliovlabs]

What

• Updated some parameters description to add Map as an allowed value for the block reference parameter, for example in the eth_getBalance method.

Why

• We are refactoring RSKj error handling behavior to align it with Geth's, some of this changes need to be added to the documentation.

Refs

• (optional: include links to other issues, PRs, tickets, etc)

[owans]

Suggested change

	RPC#the-default-block-parameter), or a map containing a block hash string, under the key `"blockHash"` or a string hexcadecimal number, under the key `"blockNumber"`.
	RPC#the-default-block-parameter), or a map containing a block hash string, under the key `"blockHash"` or a string hexadecimal number, under the key `"blockNumber"`.

[owans]

Suggested change

	| `rsk_getRawBlockHeaderByNumber` | YES | Obtains the RLP encoded block header used for SPV, if this is hashed using Keccack256 it gives the block hash. This function takes the block number (in hexa) or the string "latest" "pending" "genesis". |
	| `rsk_getRawBlockHeaderByNumber` | YES | Obtains the RLP encoded block header used for SPV, if this is hashed using Keccak256, it gives the block hash. This function takes the block number (in hexa) or the string "latest", "pending", "genesis". |

[owans]

Suggested change

	| `rsk_getRawBlockHeaderByHash` | YES | Obtains the RLP encoded block header used for SPV, if this is hashed using Keccack256 it gives the block hash. This function takes the block hash as parameter. |
	| `rsk_getRawBlockHeaderByHash` | YES | Obtains the RLP encoded block header used for SPV, if this is hashed using Keccak256 it gives the block hash. This function takes the block hash as parameter. |

[owans]

@rmoreliovlabs Any update on this?

[rmoreliovlabs]

Hello, @owans Sorry for the late reply, we divided the task of updating these details into multiple subtasks, so I'll move my and your changes to the corresponding subtask's PR and close this one.