replace trailing whitespace with blackslash in README.md

As an alternative to the markdown trailing whitespace as a line
break, we use a trailing blackslash as a markdown line break.

2000/bellard/README.md

@@ -1,9 +1,9 @@
 # Most Specific Output
 
-Fabrice Bellard  
-451 chemin du mas de Matour  
-34790 Grabels  
-France  
+Fabrice Bellard\
+451 chemin du mas de Matour\
+34790 Grabels\
+France\
 <https://bellard.org>
 
 ## To build: