Improve usage example in readme (#48)

Co-authored-by: Sindre Sorhus <[email protected]>

Author: papb

index.d.ts

@@ -19,6 +19,8 @@ It will replace single-line comments `//` and multi-line comments `/**\/` with w
 
 @example
 ```
+import stripJsonComments = require('strip-json-comments');
+
 const json = `{
 	// Rainbows
 	"unicorn": "cake"

readme.md

@@ -24,6 +24,8 @@ $ npm install strip-json-comments
 ## Usage
 
 ```js
+const stripJsonComments = require('strip-json-comments');
+
 const json = `{
 	// Rainbows
 	"unicorn": /* ❤ */ "cake"