Helper text to describe opcode behavior

[cpacia]

It would be a nice feature to have to display some text, possibly upon pressing some F button for help, that describes the function of the next opcode to be executed and the stack transformation to be expected.

[bitjson]

If it's helpful, bitcoin-ts has a set of consistent descriptions for every opcode which you could use:

• descriptions for opcodes common to all bitcoin forks
• descriptions unique to BCH

[zquestz]

That is super useful, thanks @bitjson =)

[bitjson]

Glad to help! Here are the latest versions:

• descriptions for opcodes common to all bitcoin forks
• descriptions unique to BCH