Create an Introductory Doc Page in the `docs/` Folder

[manish3299]

## Create an Introductory Documentation Page

Description:
Set up a docs/ directory if it doesn’t already exist and add an introduction.md file. This file should explain:

• What React-A11y-Assist is
• How to get started
• Key features and usage examples

Steps:

1. Create a docs/ folder in the root directory.
2. Inside docs/, create a file named introduction.md.
3. Add sections for an overview, installation instructions, and a simple example.
4. Link this documentation in the README.