Update "Validation files" example (#2046)

README.md

@@ -135,10 +135,9 @@ The data consists of parallel source (`src`) and target (`tgt`) data containing
 Validation files are used to evaluate the convergence of the training. It usually contains no more than 5k sentences.
 
 ```text
-$ head -n 3 toy-ende/src-train.txt
+$ head -n 2 toy-ende/src-train.txt
 It is not acceptable that , with the help of the national bureaucracies , Parliament 's legislative prerogative should be made null and void by means of implementing provisions whose content , purpose and extent are not laid down in advance .
 Federal Master Trainer and Senior Instructor of the Italian Federation of Aerobic Fitness , Group Fitness , Postural Gym , Stretching and Pilates; from 2004 , he has been collaborating with Antiche Terme as personal Trainer and Instructor of Stretching , Pilates and Postural Gym .
-" Two soldiers came up to me and told me that if I refuse to sleep with them , they will kill me . They beat me and ripped my clothes .
 ```
 
 We need to build a **YAML configuration file** to specify the data that will be used: