We can have more than one; eg we might offer both bech32 and a p2sh
address, and in future we might offer v1 segwit, etc.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We don't handle \u, since we assume everyone sane is using UTF-8. We'd
still have to reject '\u0000' and maybe other weird cases if we did.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>