message: add withdraw methods to documentation
diff: @@ -48,23 +48,40 @@ const matic = new Matic({
  // matic.wallet = <private-key> // Use metamask provider or use WalletConnect provider instead.
  // Approve token for deposit
  -await matic.approveTokens(
  +await matic.approveTokensForDeposit(
  token, // Token address,
  - amount // Token amount for approval (in wei)
  + amount, // Token amount for approval (in wei)
  + options // transaction fields
  )
  // Deposit token into Matic chain. Remember to call `approveTokens` before
  await matic.depositTokens(
  token, // Token address
  user, // User address (in most cases, this will be sender's address),
  - amount // Token amount for deposit (in wei)
  + amount, // Token amount for deposit (in wei)
  + options // transaction fields
  )
  // Transfer token on Matic
  await matic.transferTokens(
  token, // Token address
  user, // Recipient address
  - amount // Token amount for deposit (in wei)
  + amount, // Token amount for deposit (in wei)
  + options // transaction fields
  +)
  +
  +// Initiate withdrawal of funds from Matic and retrieve the Transaction id
  +await matic.startWithdraw(
  + token, // Token address
  + amount, // Token amount for withdraw (in wei)
  + options // transaction fields
  +)
  +
  +// Withdraw funds from the Matic chain using the Transaction id generated from the 'startWithdraw' method
  +// after header has been submitted to mainchain
  +await matic.withdraw(
  + txId, // Transaction id generated from the 'startWithdraw' method
  + options // transaction fields
  )
  ```
  