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.

2004/arachnid/README.md

@@ -1,7 +1,7 @@
 # Best use of Vision
 
-Nick Johnson  
-New Zealand  
+Nick Johnson\
+New Zealand\
 <https://web.archive.org/web/20051030162356/http://www.notdot.net/>