Add support for finalized tag. (#728)

* Add support for finalized tag.

Signed-off-by: bgravenorst <byron.gravenorst@consensys.net>

* Update docs/developers/reference/api/linea-estimategas.mdx

safe not supported

* Update docs/developers/reference/api/linea-getproof.mdx

safe not supported

---------

Signed-off-by: bgravenorst <byron.gravenorst@consensys.net>
Co-authored-by: m4sterbunny <harrie.bickle@consensys.net>

docs/developers/guides/finalized-block.mdx

@@ -6,24 +6,34 @@ image: /img/socialCards/retrieve-finalized-l2-blocks.jpg
 A finalized L2 block is a block on an L2 blockchain (Linea) that has been confirmed and validated
 by the L1 blockchain (Ethereum), ensuring its immutability and security.
 
-Linea doesn't currently support the Ethereum-standard `finalized` block parameter tag, meaning you
-cannot use the tag in JSON-RPC API calls to retrieve blocks that have been confirmed by the L1
-network. This includes, for example, methods where you can specify a block parameter, such as
-[`linea_estimateGas`](../reference/api/linea-estimategas.mdx).
+There are two methods to obtain the current finalized block:
 
-:::note
-Support for the `finalized` block parameter is planned in a future Linea release.
-:::
+- [Use the `finalized` block parameter tag](#use-the-finalized-tag) in JSON-RPC API calls.
+- [Query the Linea L1 rollup contract](#query-the-rollup-contract).
 
-This limitation requires you to query the [Linea L1 rollup contract](https://etherscan.io/address/0xd19d4b5d358258f05d7b411e21a1460d11b0876f#readProxyContract)
-to retrieve the value of the current finalized L2 block number stored in the `currentL2BlockNumber`
-variable.
+## Use the `finalized` tag
 
-## Prerequisites
+Use the `finalized` tag in API calls to specify a block that has been confirmed by the L1
+network. For example, here the `eth_getBlockByNumber` method returns information about the current
+finalized block:
+
+```bash
+curl https://rpc.linea.build \
+ -X POST \
+ -H "Content-Type: application/json" \
+ -d '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["finalized",false],"id":1}'
+```
+
+## Query the rollup contract
+
+Query the [Linea L1 rollup contract](https://etherscan.io/address/0xd19d4b5d358258f05d7b411e21a1460d11b0876f#readProxyContract)
+to retrieve the value of the current finalized L2 block number stored in the `currentL2BlockNumber` variable.
+
+### Prerequisites
 
 - [Download and install Node.js](https://nodejs.org/en)
 
-## Create the script
+### Create the script
 
 1. In your project folder, initialize the project and install the `web3` package:
 

docs/developers/reference/api/linea-estimategas.mdx

@@ -61,10 +61,13 @@ using `linea_estimateGas` for more accurate results.
  - `value`: _\[optional]_ Hexadecimal value of the value sent with this transaction.
  - `data`: _\[optional]_ Hash of the method signature and encoded parameters. See the
  [Ethereum contract ABI specification](https://docs.soliditylang.org/en/latest/abi-spec.html).
- - `block number`: _\[optional]_ A string representing a block number, or one of the string tags `latest`, `earliest`, or
- `pending`. See the [default block parameter](https://ethereum.org/en/developers/docs/apis/json-rpc/#default-block).
- You can [query the L1 rollup contract](../../guides/finalized-block.mdx) to retrieve the current finalized block.
+ - `block number`: _\[optional]_ A string representing a block number, or one of the string tags `latest`, `earliest`,
+ `pending`, or `finalized`.
 
+ :::note
+ A `finalized` block is a block on an L2 blockchain (Linea) that has been confirmed and validated by
+ the L1 blockchain (Ethereum).
+ :::
 
 ## Returns
 

docs/developers/reference/api/linea-getproof.mdx

@@ -16,21 +16,17 @@ The supplied block parameter must be an L2 block that has been finalized on L1.
 
 In the [example response](#response) the account exists but the slot does not.
 
-:::info important
-
-Linea currently does not support the block parameter `finalized`, meaning that to get the current
-finalised block on the L1, users must [retrieve the value from the `currentL2BlockNumber`](../../guides/finalized-block.mdx)
-variable in the [LineaRollup L1 contract](https://etherscan.io/address/0xd19d4b5d358258f05d7b411e21a1460d11b0876f#readProxyContract).
-
-:::
-
 ## Parameters
 
 - `address`: A string representing the address (20 bytes) for which the proof is requested.
 - `storageKeys`: An array of 32-byte storage keys to be proofed and included.
-- `blockParameter`: A hexadecimal block number, or one of the string tags `latest`, `earliest`, or
- `pending`. See the [default block parameter](https://ethereum.org/en/developers/docs/apis/json-rpc/#default-block).
- You can [query the L1 rollup contract](../../guides/finalized-block.mdx) to retrieve the current finalized block.
+- `blockParameter`: A hexadecimal block number, or one of the string tags `latest`, `earliest`,
+ `pending`, or `finalized`.
+
+ :::note
+ A `finalized` block is a block on an L2 blockchain (Linea) that has been confirmed and validated by
+ the L1 blockchain (Ethereum).
+ :::
 
 ## Returns