Enable frozen string literals.

Make all string literals immutable by default.

app/components/application_component.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class ApplicationComponent < ViewComponent::Base
   delegate :link_to_user, :time_ago_in_words_tagged, :format_text, :external_link_to, :tag_class, to: :helpers
   delegate :edit_icon, :delete_icon, :undelete_icon, :flag_icon, :upvote_icon, :downvote_icon, :link_icon, :sticky_icon, :unsticky_icon, to: :helpers

app/components/comment_votes_tooltip_component.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This component represents the tooltip that displays when you hover over a comment's score.
 class CommentVotesTooltipComponent < ApplicationComponent
   attr_reader :comment, :current_user

app/components/post_gallery_component.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+#
 # A component that displays a gallery of post thumbnails.
 #
 # There are two types of galleries:

app/components/post_navbar_component.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class PostNavbarComponent < ApplicationComponent
   extend Memoist