Remove invalid -S option from rdoc_options.

Author: djberg96

coderay.gemspec

@@ -28,6 +28,6 @@ Gem::Specification.new do |s|
   s.executables   = `git ls-files -- bin/*`.split("\n").map { |f| File.basename(f) }
   s.require_paths = ['lib']
 
-  s.rdoc_options      = '-SNw2', "-m#{readme_file}", '-t CodeRay Documentation'
+  s.rdoc_options      = '-Nw2', "-m#{readme_file}", '-t CodeRay Documentation'
   s.extra_rdoc_files  = readme_file
 end