infra: improved theme preview script markdown

      repo: "github-readme-stats",

      body: `

      \rTheme preview (bot)  

      \r![](${url})

      \rtitle-color: <code>#${titleColor}</code>

      \ricon-color: <code>#${iconColor}</code>

      \rtext-color: <code>#${textColor}</code>

      \rbg-color: <code>#${bgColor}</code>

      \r[![](${url})](${url})

      `,

      issue_number: pullRequestId,

    });