correct to preview html file

frederichecht · frederichecht · commit f70e895591cc · 2021-12-13T14:39:14.000+01:00
diff --git a/README.md b/README.md
@@ -2,15 +2,15 @@
 
 ## 2021
 
-[the index ](https://github.com/FreeFem/FreeFem-days/blob/master/2021/index.html))
+[the index ](https://htmlpreview.github.io/?https://github.com/FreeFem/FreeFem-days/blob/master/2021/index.html)
 
 ## 2020
 
-[the index ](https://github.com/FreeFem/FreeFem-days/blob/master/2020/index.html))
+[the index ](https://htmlpreview.github.io/?https://github.com/FreeFem/FreeFem-days/blob/master/2020/index.html)
 
 ## 2019
 
-[the index ](https://github.com/FreeFem/FreeFem-days/blob/master/2019/index.html))
+[the index ](https://htmlpreview.github.io/?https://github.com/FreeFem/FreeFem-days/blob/master/2019/index.html)
 
 
 | Speaker | Day 1 - 2019 |

-Original file line number
+Diff line change
 ## 2021
 -[the index ](https://github.com/FreeFem/FreeFem-days/blob/master/2021/index.html))
 +[the index ](https://htmlpreview.github.io/?https://github.com/FreeFem/FreeFem-days/blob/master/2021/index.html)
 ## 2020
 -[the index ](https://github.com/FreeFem/FreeFem-days/blob/master/2020/index.html))
 +[the index ](https://htmlpreview.github.io/?https://github.com/FreeFem/FreeFem-days/blob/master/2020/index.html)
 ## 2019
 -[the index ](https://github.com/FreeFem/FreeFem-days/blob/master/2019/index.html))
 +[the index ](https://htmlpreview.github.io/?https://github.com/FreeFem/FreeFem-days/blob/master/2019/index.html)
 | Speaker | Day 1 - 2019 |