docs: add tree-sitter grammar and comprehensive editor support

[Omzee15]

Description

This PR adds comprehensive editor support documentation, including the community-created tree-sitter grammar and VS Code extension, to address issues #143 and #99.

Changes Made

• ✅ Added Editor Support section to README.md with detailed documentation
• ✅ Documented tree-sitter-toon grammar with usage examples
• ✅ Included VS Code extension with full feature list
• ✅ Added Neovim configuration example for tree-sitter integration
• ✅ Updated with comprehensive editor support
• ✅ Added Editor Support to table of contents in README

Editor Support Documented

Tree-sitter Grammar

• GitHub: https://github.com/3swordman/tree-sitter-toon
• Supports: Neovim, Helix, Emacs, Zed, and other Tree-sitter compatible editors
• Includes Neovim configuration example

VS Code Extension

• Marketplace: https://marketplace.visualstudio.com/items?itemName=vishalraut.vscode-toon
• Features: Syntax highlighting, validation, conversion, snippets, token optimization
• GitHub: https://github.com/vishalraut2106/vscode-toon

Other Editors

• Vim/Neovim: toon.nvim plugin
• Fallback: YAML syntax highlighting

Benefits

• Makes it easy for developers to discover and use editor tooling
• Provides clear setup instructions for different editors
• Acknowledges community contributions
• Improves developer experience across multiple editors

Closes #143
Closes #99