Replace Trix with Lexxy

app/controllers/autocompletable/users_controller.rb

@@ -1,11 +1,22 @@
 class Autocompletable::UsersController < ApplicationController
   def index
     set_page_and_extract_portion_from find_autocompletable_users.with_attached_avatar.ordered, per_page: 20
+
+    respond_to do |format|
+      format.html { render layout: false } # <lexxy-prompt-item> elements for the mentions prompt
+      format.json
+    end
   end
 
   private
     def find_autocompletable_users
-      params[:query].present? ? users_scope.active.filtered_by(params[:query]) : users_scope.active
+      query.present? ? users_scope.active.filtered_by(query) : users_scope.active
+    end
+
+    # The rich text editor's mentions prompt filters with `filter`, the
+    # autocomplete inputs with `query`
+    def query
+      params[:filter].presence || params[:query].presence
     end
 
     def users_scope