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.

1998/bas2/README.md

@@ -1,9 +1,9 @@
 # Best Small Program
 
-Bas de Bakker  
-Pica, Centre for Library Automation  
-Statenweg 154 B     (home address)  
-3039 JN Rotterdam  
+Bas de Bakker\
+Pica, Centre for Library Automation\
+Statenweg 154 B     (home address)\
+3039 JN Rotterdam\
 The Netherlands
 
 ## To build: