Function map

map(
    program: Program,
    callback: (
        instruction: Instruction,
        index: number,
        program: Program,
    ) => Instruction,
): Program
Rewrites every instruction.
Parameters
- program: Program
  Program to map.
- callback: (instruction: Instruction, index: number, program: Program) => Instruction
  Returns the replacement for each instruction.
Returns Program
A new program; the input is left untouched.
Example
```
const redacted = map(program, (instruction) =>
  instruction.opcode === Opcode.TXT_CHUNK ? redact(instruction) : instruction,
);
```