sources: don't escape Unicode characters in tag search URLs.

Fix it so that Unicode characters aren't unnecessarily percent-encoded when generating tag search
URLs. For example, generate URLs like this:

* https://www.pixiv.net/tags/オリジナル/artworks

Not like this:

* https://www.pixiv.net/tags/%E3%82%AA%E3%83%AA%E3%82%B8%E3%83%8A%E3%83%AB/artworks

app/logical/source/extractor/moebooru.rb

@@ -23,7 +23,7 @@ module Source
 
       def tags
         api_response[:tags].to_s.split.map do |tag|
-          [tag, "https://#{domain}/post?tags=#{CGI.escape(tag)}"]
+          [tag, "https://#{domain}/post?tags=#{Danbooru::URL.escape(tag)}"]
         end
       end