[FEAT]: Copilot output as JSON format

[moutonjeremy]

Describe the need

I would like to be able to choose the output type of the copilot command (JSON for example) to be able to parse the result easily.
For example for a script to generate messages for git commit.

Relevant terminal output

$ gh copilot suggest "write a commit message for the x.go file following this modification $(git diff x.go)"
{ "suggest_result": "Update ttt function ....." }

With this, we can have a script like this:

#!/bin/bash

files=$(git status --porcelain | awk '{print $2}')

for file in $files; do
  echo "Analise file: $file"
  prompt="Write a commit message for this file $file with this modification $(git diff $file)"

  commit_message=$(gh copilot suggest --json $prompt | jq -r '.suggest_result')

  echo "Commit message for $file: $commit_message"
done