Document consensus rules from Zcash spec: 4.5 Output Descriptions

[mpguerra]

For each consensus rule:

• check that the rule is implemented in Zebra
• make sure the latest version of the rule is quoted in the docs for the code that implements it
• make sure the code implements the latest version of the rule

Consensus rules

https://zips.z.cash/protocol/protocol.pdf#outputdesc

See also ZIP-216: Require Canonical Point Encodings

Implementation

• Implement ZIP-216: Require Canonical Point Encodings #1798
  • PR: Implement ZIP-216: Canonical Jubjub Point Encodings zkcrypto/jubjub#43