feat: Add math rendering support to markdown

[IAdityaKaushal]

Type of changes

• Bug fix
• New feature
• Documentation / docstrings
• Tests
• Other

Checklist

• I've run the latest black with default args on new code.
• I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
• I've added tests for new code.
• I accept that @willmcgugan may be pedantic in the code review.

Description

This PR adds support for rendering LaTeX-style mathematical expressions in markdown output. This addresses issue #3159 which requested the ability to display mathematical equations in terminal markdown.

Features Added:

• New MathRenderer class that converts LaTeX math syntax to Unicode representation
• Integration of math rendering into the existing markdown processing pipeline
• Support for both inline math ($...$) and block math ($$...$$) expressions
• Comprehensive test suite for math rendering functionality

Implementation Details:

• The renderer supports common LaTeX symbols including Greek letters, operators, superscripts, and subscripts
• Preserves spacing in simple equations for better readability
• Gracefully falls back to plaintext when symbols cannot be rendered

This enhancement significantly expands Rich's capabilities for scientific and educational applications, allowing users to render mathematical expressions directly in the terminal.

Fixes/supports feature request #3159 linked here
#3159