Bitcoinjs-lib: update comment to say bech32 as well?

[mandelmonkey]

https://github.com/bitcoinjs/bitcoinjs-lib/blob/e0f24fdd46e11533a7140e02dc43b04a4cc4522e/src/transaction_builder.js#L607

this is pedantic I know lol but im using the library to walk my self through how segwit addresses and transactions are made

I noticed on this line it says

// Attempt to get a script if it's a base58 address string

should it say?

// Attempt to get a script if it's a base58 or bech32 address string

[dabura667]

Thanks for the report!

Closing in favor of #980