docs(readme): update toc

README.md

@@ -22,23 +22,23 @@ It currently uses `crypto` and [`sha3`](https://github.com/phusion/node-sha3) in
 
 ## Table of Contents
 
-- [Install](#install)
-  - [In Node.js through npm](#in-nodejs-through-npm)
-  - [Use in a browser with browserify, webpack or any other bundler](#use-in-a-browser-with-browserify-webpack-or-any-other-bundler)
-  - [Use in a browser Using a script tag](#use-in-a-browser-using-a-script-tag)
+* [Table of Contents](#table-of-contents)
+* [Install](#install)
+  + [In Node.js through npm](#in-nodejs-through-npm)
+  + [Use in a browser with browserify, webpack or any other bundler](#use-in-a-browser-with-browserify-webpack-or-any-other-bundler)
+  + [Use in a browser Using a script tag](#use-in-a-browser-using-a-script-tag)
     - [Gotchas](#gotchas)
-- [Usage](#usage)
-- [Examples](#examples)
-  - [Multihash output](#multihash-output)
-  - [Raw digest output](#raw-digest-output)
-- [API](#api)
-  - [`multihashing(buf, func, length)`](#multihashingbuf-func-length)
-  - [`digest(buf, func, length)`](#digestbuf-func-length)
-  - [`createHash(func, length)`](#createhashfunc-length)
-  - [`functions`](#functions)
-- [Maintainers](#maintainers)
-- [Contribute](#contribute)
-- [License](#license)
+* [Usage](#usage)
+* [Examples](#examples)
+  + [Multihash output](#multihash-output)
+* [API](#api)
+  + [`multihashing(buf, func, [length,] callback)`](#multihashingbuf-func-length-callback)
+  + [`digest(buf, func, [length,] callback)`](#digestbuf-func-length-callback)
+  + [`createHash(func)`](#createhashfunc)
+  + [`functions`](#functions)
+* [Maintainers](#maintainers)
+* [Contribute](#contribute)
+* [License](#license)
 
 ## Install