feat: add filecoinAddressToETHAddressV1 docs

reference/json-rpc/eth.md

@@ -32,6 +32,51 @@ Inputs:
 
 Response: `"f01234"`
 
+## FilecoinAddressToEthAddress
+
+FilecoinAddressToEthAddress converts any Filecoin address to an EthAddress.
+
+This method supports all Filecoin address types:
+
+- f0 and f4 addresses: Converted directly.
+- f1/f2/f3 addresses: First converted to their corresponding f0 ID address, then to an EthAddress.
+
+> **Note:**
+> 
+> f0 ID addresses are not permanent and can be affected by chain reorganizations. To account for this,
+> the API includes a `blkNum` parameter, which specifies the block number that is used to determine the tipset state to use for converting an
+> f1/f2/f3 address to an f0 address. This parameter functions similarly to the `blkNum` parameter in the existing `EthGetBlockByNumber` API.
+> See [Alchemy Docs - eth_getBlockByNumber](https://docs.alchemy.com/reference/eth-getblockbynumber) for more details.
+
+Requirements:
+
+- For f1/f2/f3 addresses, they must be instantiated on-chain, as f0 ID addresses are only assigned to actors when they are created on-chain.
+  The simplest way to instantiate an address on chain is to send a transaction to the address.
+
+Parameters:
+
+- filecoinAddress: The Filecoin address to convert.
+- blkNum: The block number or state for the conversion. Defaults to "finalized" for maximum safety.
+  Possible values: "pending", "latest", "finalized", "safe", or a specific block number represented as hex.
+
+Perms: read
+
+Inputs:
+
+```json
+["f410", "finalized"]
+
+["f1", "safe"]
+```
+
+Response:
+
+```json
+"0x5cbeecf99d3fdb3f25e309cc264f240bb0664031"
+
+"0x1234567890abcdef1234567890abcdef12345678"
+```
+
 ## EthBlockNumber
 
 EthBlockNumber returns the height of the latest (heaviest) TipSet
@@ -48,7 +93,7 @@ Perms: read
 
 Inputs:
 
-```json
+```jsona
 [
   {
     "from": "0x5cbeecf99d3fdb3f25e309cc264f240bb0664031",
@@ -823,4 +868,4 @@ Inputs:
 ["0x37690cfec6c1bf4c3b9288c7a5d783e98731e90b0a4c177c2a374c7a9427355e"]
 ```
 
-Response: `true`
+Response: `true`