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.

2001/coupard/README.md

@@ -1,10 +1,10 @@
 # Most obfuscated sound
 
-Pierre-Philippe Coupard  
-Lineo, Inc.  
-ATTN : Pierre-Philippe Coupard  
-390 South 400 West  
-Lindon, UT 84042  
+Pierre-Philippe Coupard\
+Lineo, Inc.\
+ATTN : Pierre-Philippe Coupard\
+390 South 400 West\
+Lindon, UT 84042\
 US