DEV: Move settings to linkify to the serializer code. (#14553)

We aren't translating these settings, so it makes more sense to move them into the code. I added an instance method so plugins can add mappings for custom reasons.

lib/plugin/instance.rb

@@ -950,6 +950,26 @@ class Plugin::Instance
     DiscoursePluginRegistry.register_presence_channel_prefix([prefix, block], self)
   end
 
+  # Register a ReviewableScore setting_name associated with a reason.
+  # We'll use this to build a site setting link and add it to the reason's translation.
+  #
+  # If your plugin has a reason translation looking like this:
+  #
+  #   my_plugin_reason: "This is the reason this post was flagged. See %{link}."
+  #
+  # And you associate the reason with a setting:
+  #
+  #   add_reviewable_score_link(:my_plugin_reason, 'a_plugin_setting')
+  #
+  # We'll generate the following link and attach it to the translation:
+  #
+  #   <a href="/admin/site_settings/category/all_results?filter=a_plugin_setting">
+  #     a plugin setting
+  #   </a>
+  def add_reviewable_score_link(reason, setting_name)
+    DiscoursePluginRegistry.register_reviewable_score_link({ reason: reason.to_sym, setting: setting_name }, self)
+  end
+
   protected
 
   def self.js_path