Fix fenced code blocks

[jemiam]

When triple backticks are in results for terraform command, wrapCode method uses HTML tags(pre + code) to escape it. But currently these tags are also escaped so it doesn't work as intended.

This PR fixes the bug by

• When triple backticks are not in results, use triple backticks
• When only triple backticks are in results and triple tilde not in results, use triple tilde
• When both triple backticks and triple tilde are in results, use pre + code tags without HTML escape

[suzuki-shunsuke]

Thank you for your contribution!

[suzuki-shunsuke]

📝
https://pkg.go.dev/html/template#HTML
https://pkg.go.dev/html/template#HTMLEscapeString

I didn't know the syntax ~~~.

[jemiam]

Forgot to add nolint:gosec comment 🙂

[suzuki-shunsuke]

Thank you!