📚 Switch back to rdoc's darkfish generator (🚧TMP)

The "aliki" generator is a big (overdue) step forward for rdoc.  But, at
least for now, aliki's issues with TOC and headings are a bit too much
for me.  Hopefully I'll find some time to fix them (or post some bug
reports).

I also need to adapt some of the stylesheet tweaks (and submit them back
to rdoc as suggestions for better defaults).

Author: nevans

rakelib/rdoc.rake

@@ -51,5 +51,5 @@ RDoc::Task.new do |doc|
   doc.rdoc_dir   = "doc"
   doc.rdoc_files = FileList.new %w[lib/**/*.rb *.rdoc *.md]
   doc.options << "--template-stylesheets" << "docs/styles.css"
-  # doc.generator  = "hanna"
+  doc.generator  = "darkfish" # TODO: fix issues with aliki
 end