add these two lines to @file{Documentation/web/server/robots.txt}:
@example
-Disallow: /doc/v2.@var{OLD-STABLE/}
-Disallow: /doc/v2.@var{NEW-DEVELOPMENT/}
+Disallow: /doc/v2.@var{OLD-STABLE}/
+Disallow: /doc/v2.@var{NEW-DEVELOPMENT}/
@end example
@end itemize