Fix Markdown typo.

README.md

@@ -68,15 +68,15 @@ __NOTE__: It is possible to use the notebooks directly from some IDEs like [VSCo
 
 It is possible to execute the notebooks from a Docker machine by simply typing:
 
-```
+````
 docker run -v $PWD:/home/formation/gettingstartedwithmoderncpp -p 8888:8888 registry.gitlab.inria.fr/formations/cpp/gettingstartedwithmoderncpp/xeus-cling:latest
-```
+````
 
 or 
 
 ````
 docker run -v $PWD:/home/formation/gettingstartedwithmoderncpp -p 8888:8888 registry.gitlab.inria.fr/formations/cpp/gettingstartedwithmoderncpp/xeus-cling-and-compilers:latest
-```
+````
 
 Then just type [http://localhost:8888/](http://localhost:8888/) in your browser.