2157e69857 Document the `all` module (Tobin C. Harding)
Pull request description:
Improve documentation on the `all` module by doing:
- Document guarantee that `all` will only ever contain opcode constants
- Fix stale/incorrect code comment
Done as follow up to #1295
ACKs for top commit:
apoelstra:
ACK 2157e69857
Kixunil:
ACK 2157e69857
Tree-SHA512: 4df091bbdce7b9ba73caabd74b80f9e8c0a30fa2f9a20ed9b75542e71a204e5cd82698a74bebbd6f0beab55ecd807154d1b7d27a787cc9dede7abbd20a0a4ad5