Fix whole-word selection and i18n: Add Japanese translation for Whole-word (#8004)

* Add Japanese translation for "Whole word" and add it's description.

* Fix to enable "Whole-word" selection.

app/controllers/filters_controller.rb

@@ -52,6 +52,6 @@ class FiltersController < ApplicationController
   end
 
   def resource_params
-    params.require(:custom_filter).permit(:phrase, :expires_in, :irreversible, context: [])
+    params.require(:custom_filter).permit(:phrase, :expires_in, :irreversible, :whole_word, context: [])
   end
 end