Update link directly to the bip39 file

Author: skywinder

bip-0039.mediawiki

@@ -165,7 +165,8 @@ Rust:
 Swift:
 * https://github.com/CikeQiu/CKMnemonic
 * https://github.com/yuzushioh/WalletKit
-* https://github.com/matter-labs/web3swift (`BIP39` public class)
+* https://github.com/matter-labs/web3swift/blob/develop/Sources/web3swift/KeystoreManager/BIP39.swift
+* https://github.com/matter-labs/web3swift/blob/develop/Sources/web3swift/KeystoreManager/BIP39.swift
 
 C++:
 * https://github.com/libbitcoin/libbitcoin/blob/master/include/bitcoin/bitcoin/wallet/mnemonic.hpp