docs: update README to enhance Table of Contents and add raw transformations parameter

Author: manu4543

README.md

@@ -10,6 +10,36 @@ For additional details, refer to the [ImageKit REST API documentation](https://i
 
 If you are looking to integrate file uploads in browsers, use one of our [frontend SDKs](https://imagekit.io/docs/quick-start-guides#front-end).
 
+## Table of Contents
+
+- [Installation](#installation)
+- [Usage](#usage)
+  - [Request & Response types](#request--response-types)
+- [File uploads](#file-uploads)
+- [URL generation](#url-generation)
+  - [Basic URL generation](#basic-url-generation)
+  - [URL generation with transformations](#url-generation-with-transformations)
+  - [URL generation with image overlay](#url-generation-with-image-overlay)
+  - [URL generation with text overlay](#url-generation-with-text-overlay)
+  - [URL generation with multiple overlays](#url-generation-with-multiple-overlays)
+  - [Signed URLs for secure delivery](#signed-urls-for-secure-delivery)
+  - [Using Raw parameter for custom transformations](#using-raw-parameter-for-custom-transformations)
+- [Authentication parameters for client-side uploads](#authentication-parameters-for-client-side-uploads)
+- [Webhook verification](#webhook-verification)
+  - [Verifying webhook signatures](#verifying-webhook-signatures)
+- [Handling errors](#handling-errors)
+  - [Retries](#retries)
+  - [Timeouts](#timeouts)
+- [Advanced Usage](#advanced-usage)
+  - [Accessing raw Response data (e.g., headers)](#accessing-raw-response-data-eg-headers)
+  - [Logging](#logging)
+  - [Making custom/undocumented requests](#making-customundocumented-requests)
+  - [Customizing the fetch client](#customizing-the-fetch-client)
+  - [Fetch options](#fetch-options)
+- [Semantic versioning](#semantic-versioning)
+- [Requirements](#requirements)
+- [Contributing](#contributing)
+
 ## Installation
 
 ```sh
@@ -264,6 +294,26 @@ const permanentSignedUrl = client.helper.buildSrc({
 // Result: URL with signature parameter (?ik-s=signature)
 ```
 
+### Using Raw parameter for custom transformations
+
+ImageKit frequently adds new transformation parameters that might not yet be documented in the SDK. You can use the `raw` parameter to access these features or create custom transformation strings:
+
+```ts
+// Using raw parameter for custom transformations
+const customTransformUrl = client.helper.buildSrc({
+  urlEndpoint: 'https://ik.imagekit.io/your_imagekit_id',
+  src: '/path/to/image.jpg',
+  transformation: [
+    {
+      width: 400,
+      height: 300,
+      raw: 'something-new', // Custom contrast transformation
+    },
+  ],
+});
+// Result: https://ik.imagekit.io/your_imagekit_id/path/to/image.jpg?tr=w-400,h-300,something-new
+```
+
 ## Authentication parameters for client-side uploads
 
 Generate authentication parameters for secure client-side file uploads:
@@ -595,8 +645,6 @@ const client = new ImageKit({
 });
 ```
 
-## Frequently Asked Questions
-
 ## Semantic versioning
 
 This package generally follows [SemVer](https://semver.org/spec/v2.0.0.html) conventions, though certain backwards-incompatible changes may be released as minor versions: