Fix: Replace duplicate callout headings with ARIA-labeled sections

[reshma045]

Description

This PR addresses issue #871 by replacing repeated heading elements (<h5>Tip</h5>, <h5>Note</h5>, etc.) used in callout blocks with <section> elements that include accessible ARIA labels instead.

Changes Made

• Modified src/components/callout/index.astro:
  • Replaced <h5> heading with <section role="region" aria-label="...">
  • Ensured the title is passed as an ARIA label instead of a heading element.
  • Removed heading tags to prevent unnecessary duplication in the document outline.

Before vs After

• Before: Multiple <h5>Tip</h5> or <h5>Note</h5> headings were present, cluttering the document structure and affecting accessibility.
• After: Replaced with <section aria-label="Tip">...</section> and similar, improving semantic clarity and screen reader navigation.

Screenshot

Before

After

Related Issue

Closes #871