Guide Improvement: Add examples for double-sharp and double-flat usage in musical contexts (#3855)

[anandritishaa07]

Summary

This PR addresses issue #3855 by enhancing the guide with concrete examples that illustrate practical usage of double-sharps and double-flats in musical notation. These additions aim to improve clarity for readers wondering when and why such accidentals appear in standard musical contexts.

Added Examples

• G♯ Major Scale: Demonstrates F double-sharp (Fx) as the leading tone
• D♯ Major Scale: Includes both C double-sharp and F double-sharp
• F♭ Major Scale: Contains B double-flat
• Béla Bartók's Mikrokosmos:
  • Piece No. 136 ("Whole-tone Scale") includes double-flats
  • Sixth measure of Mikrokosmos example cited contains double-flats as well

Resources Used

• Mikrokosmos (Wikipedia)

Motivation

Musicians and learners often question the relevance of double accidentals. Adding these examples makes our documentation more pedagogical and concrete.

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Let me know if anything needs refining!

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[walterbender]

While I very much appreciate the inclusion of these examples, I think the overall discussion is a bit over the head of most of our users. Especially in that you introduce a number of terms that I don't think the average MB user would be familiar with: voice leading rules, enharmonically equivalence, theoretical key, preserve the correct intervals, theoretical spellings. I wonder if there isn't a way to explain this w/o these terms?