[Ruby-fr] Fix length of comments and french syntax

Hi,

Some comments exceed the block of code [Ruby-fr](http://learnxinyminutes.com/docs/fr-fr/ruby-fr/). Therefore, I've split the comments in two lines.

But for the interpolation, I can't split otherwise, we lost the syntax highlighting. 

Picture of the exceeding: 
![Comments](https://f.cloud.github.com/assets/309354/979591/4a775f8a-0718-11e3-8bfe-501d0c76e0f1.png)
![Interpolation](https://f.cloud.github.com/assets/309354/979595/8db91b3a-0718-11e3-8a1a-fcfeb2c6bd30.png)

And I've fixed a french syntax error.

Thanks.