README: Add rendering to HTML info.

Author: janbarasek

README.md

@@ -45,6 +45,31 @@ echo 'Changed lines: ';
 echo implode(', ', $diff->getChangedLines());
 ```
 
+Display the Diff in HTML
+------------------------
+
+Very often we need to display the differences directly in the browser, for this the native method `renderDiff()` is suitable.
+
+```php
+$left = 'First text';
+$right = 'Second text';
+
+$simpleDiff = new \Baraja\DiffGenerator\SimpleDiff;
+$diff = $![image](https://user-images.githubusercontent.com/4738758/113039971-8eb1b700-9198-11eb-9960-544be342d9ff.png)
+![image](https://user-images.githubusercontent.com/4738758/113039973-8eb1b700-9198-11eb-895f-805ea0ec470e.png)
+![image](https://user-images.githubusercontent.com/4738758/113039976-8f4a4d80-9198-11eb-928a-4b5d2b4f4533.png)
+![image](https://user-images.githubusercontent.com/4738758/113039981-8fe2e400-9198-11eb-8d95-9bcd258fc81b.png)
+![image](https://user-images.githubusercontent.com/4738758/113039978-8f4a4d80-9198-11eb-96e7-695ade2fd592.png)
+![image](https://user-images.githubusercontent.com/4738758/113039983-8fe2e400-9198-11eb-8bcd-821aae346cb0.png)
+![image](https://user-images.githubusercontent.com/4738758/113039982-8fe2e400-9198-11eb-8c32-0fd1c57d97d8.png)
+![image](https://user-images.githubusercontent.com/4738758/113039987-92453e00-9198-11eb-8da0-3208d0fd6816.png)
+simpleDiff->compare($left, $right);
+
+echo $simpleDiff->renderDiff($diff);
+```
+
+The method accepts Diff and returns valid treated HTML that can be displayed directly to the user.
+
 Comparison mode
 ---------------