Refactor structure and fix broken links in documentation

[saumyashahi]

Summary

Fix issues in the documentation by resolving broken links caused by incorrect Markdown references and reorganizing misplaced text in the toolbar and context menu sections.

• Fixes Inconsistent Heading and Description for "Context Menu" in Music Blocks Documentation #4235, Add more documentation for some context menus #2403

Key Changes

• Correct Markdown syntax for link references to make them valid.
• Move the context menu text from the toolbar section to its appropriate location in the context menu section.
• Adjust structure for clarity and accuracy to ensure sections align with their intended topics.

Testing

View the rendered documentation to confirm that the changes appear correctly in the desired format.

[saumyashahi]

@walterbender @pikurasa, I have addressed the issues and made the necessary changes. Please review the updates and let me know if there are any additional adjustments or improvements needed.