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.

1994/ldb/README.md

@@ -1,7 +1,7 @@
 # Best One-liner
 
-Laurion Burchall  
-US  
+Laurion Burchall\
+US\
 <https://web.archive.org/web/20070711215750/http://www.netspace.org/users/ldb/>