c717f7f424 Improve docs on private Witness fields (Tobin C. Harding)
Pull request description:
The `Witness` type is a reasonable complex data structure, make an effort to clarify its structure in the docs on the private fields.
Private docs only.
(Original idea pulled out of #2133.)
ACKs for top commit:
Kixunil:
ACK c717f7f424
apoelstra:
ACK c717f7f424 much clearer, thanks!
Tree-SHA512: 9d54b7eeefec97e584fb5f275049dbac0473c949fae8ab05c6961d6fc424c17a058af7037c2220ef1446af294d78c68bfee741cfeca1b18ecc402935d8069dab