Update YARD comment to avoid warning (#531)

lib/oj/mimic.rb

@@ -31,7 +31,7 @@ def []=(key, value)
   end
 
   # Loads mimic-ed JSON paths. Used by Oj.mimic_JSON().
-  # @param mimic_path [Array] additional paths to add to the Ruby loaded features.
+  # @param mimic_paths [Array] additional paths to add to the Ruby loaded features.
   def self.mimic_loaded(mimic_paths=[])
     $LOAD_PATH.each do |d|
       next unless File.exist?(d)