Squelch warning about useless variable

The title_id variable is necessary and used by ERB via binding.

lib/simplecov-html.rb

@@ -66,8 +66,10 @@ def formatted_source_file(source_file)
 
   # Returns a table containing the given source files
   def formatted_file_list(title, source_files)
-    title_id = title.gsub(/^[^a-zA-Z]+/, '').gsub(/[^a-zA-Z0-9\-\_]/, '')
-    title_id # Ruby will give a warning when we do not use this except via the binding :( FIXME
+    # Silence a warning by using the following variable to assign to itself:
+    # "warning: possibly useless use of a variable in void context"
+    # The variable is used by ERB via binding.
+    title_id = title_id = title.gsub(/^[^a-zA-Z]+/, '').gsub(/[^a-zA-Z0-9\-\_]/, '')
     template('file_list').result(binding)
   end