Docs: Fix anchor in 'docs/developer-guide/working-with-rules.md'

[Nate-Wilkins]

What is the purpose of this pull request?

[X] Documentation update

What changes did you make? (Give an overview)

Fixes the getSourceCode() anchor ref.

[eslint-github-bot]

Hi @Nate-Wilkins!, thanks for the Pull Request

The first commit message isn't properly formatted. We ask that you update the message to match this format, as we use it to generate changelogs and automate releases.

• The commit message tag must be one of the following:

  The Tag is one of the following:

  • Fix - for a bug fix.
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  • Build - changes to build process only.
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  • Chore - for anything that isn't user-facing (for example, refactoring, adding tests, etc.).

  You can use the labels of the issue you are working on to determine the best tag.

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[snitin315]

Thanks!

[mdjermanovic]

LGTM, thanks!

Can you please sign our CLA, so we could merge this?

[Nate-Wilkins]

Signed 👍

[mdjermanovic]

Thanks for contributing!