Added docs for no-literal-dollar-root and require-explicit-data-context linter rules.

[niegowski]

🚀 Summary

Added docs for no-literal-dollar-root and require-explicit-data-context linter rules.

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📌 Related issues

• See New ESLint rule: disallow implicit $root schema context #20096
• See Added 2 new rules: no-literal-dollar-root and require-explicit-data-context ckeditor5-linters-config#112

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💡 Additional information

Optional: Notes on decisions, edge cases, or anything helpful for reviewers.

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