Extend options to customize links

[paescuj]

Initial checklist

• [x] I read the support docs
• [x] I read the contributing guide
• [x] I agree to follow the code of conduct
• [x] I searched issues and couldn’t find anything (or linked relevant results below)
• [x] If applicable, I’ve added docs and tests

Description of changes

This pull request extends the link customization options as follows:

• Allow to override the default base URL (https://github.com) in the defaultBuildUrl function by passing the desired URL in the second parameter, for example:

  .use(remarkGithub, {
  buildUrl(values, defaultBuildUrl) {
    return defaultBuildUrl(values, 'https://yourwebsite.com')
  }
  })

  This is useful if you only want to change the base URL (e.g. GitHub Enterprise) and otherwise keep the default "build URL" behavior.

• Two new options to replace the issue / mention characters (# / @) with something else.

  In my case, I'm using the generated Markdown to create automated comments on GitHub pull requests. GitHub automatically notifies mentioned users and displays references in issues linking to those comments which is something I'd like to prevent in that case. With those two options I'm able to do so by inserting a zero-width space after the issue / mention characters:

  const zeroWidthSpace = '​'
  [...]
  .use(remarkGithub, {
    issueCharReplacement: `#${zeroWidthSpace}`,
    mentionCharReplacement: `@${zeroWidthSpace}`
  })

  This might be a bit specific, but I know of other applications (like Renovate) that have the same problem and could also benefit from such options. I'd be pleased if those options were adopted in remark-github, as otherwise I'd have to re-implement most of its logic again outside of it. Of course I'm open for adjustments!

---

In addition, this pull request also contains two enhancements in separate commits:

• Add dependabot to real world examples in test
• Fix build command

[paescuj]

Hi Titus! Thank you very much for your quick response and considerations! I've realized that I need to do some additional things anyway, like rewriting URLs from "plain" links. Therefore, I'm going to write an own plugin to handle all those things and I'll close this pull request. Thanks anyway!

[github-actions[bot]]

Hi! This was closed. Team: If this was merged, please describe when this is likely to be released. Otherwise, please add one of the no/* labels.

[github-actions[bot]]

Hi team! Could you describe why this has been marked as wontfix?

Thanks, — bb