Use <pre> tag for formatting

app/models/application_record.rb

@@ -1,4 +1,6 @@
 class ApplicationRecord < ActiveRecord::Base
+  include ActionView::Helpers::TagHelper
+
   class << self
     # Cached attribute has non-user assignable value calculated from other
     # attributes' values on create/update. This simplifies and speeds up

app/models/quantity.rb

@@ -98,7 +98,7 @@ class Quantity < ApplicationRecord
   }
 
   def to_s
-    name
+    tag.pre name
   end
 
   def to_s_with_depth

app/models/unit.rb

@@ -91,7 +91,7 @@ class Unit < ApplicationRecord
   end
 
   def to_s
-    symbol
+    tag.pre symbol
   end
 
   def movable?