Update README.md (#282)

## Description

Add Table of contents and fix typo in `README.md`
### Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [x] Documentation update (improves or adds clarity to existing
documentation)

### Tested on

- [x] iOS
- [x] Android

### Testing instructions

Not applicable

### Screenshots

Not applicable

### Related issues

Not applicable

### Checklist

- [x] I have performed a self-review of my code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have updated the documentation accordingly
- [x] My changes generate no new warnings

### Additional notes

<!-- Include any additional information, assumptions, or context that
reviewers might need to understand this PR. -->

Author: msluszniak

README.md

@@ -8,6 +8,18 @@
 
 **ExecuTorch** is a novel framework created by Meta that enables running AI models on devices such as mobile phones or microcontrollers. React Native ExecuTorch bridges the gap between React Native and native platform capabilities, allowing developers to run AI models locally on mobile devices with state-of-the-art performance, without requiring deep knowledge of native code or machine learning internals.
 
+**Table of contents:**
+
+- [Compatibility](#compatibility)
+- [Ready-made models 🤖](#readymade-models-)
+- [Documentation 📚](#documentation-)
+- [🦙 Quickstart - Running Llama](#-quickstart---running-llama)
+- [Minimal supported versions](#minimal-supported-versions)
+- [Examples 📲](#examples-)
+- [Warning](#warning)
+- [License](#license)
+- [What's next?](#whats-next)
+
 ## Compatibility
 
 React Native Executorch supports only the [New React Native architecture](https://reactnative.dev/architecture/landing-page).