Fix various rubocop warnings.

app/models/artist_commentary_version.rb

@@ -22,23 +22,17 @@ class ArtistCommentaryVersion < ApplicationRecord
   end
 
   def previous
-    @previous ||= begin
-      ArtistCommentaryVersion.where("post_id = ? and updated_at < ?", post_id, updated_at).order("updated_at desc").limit(1).to_a
-    end
+    @previous ||= ArtistCommentaryVersion.where("post_id = ? and updated_at < ?", post_id, updated_at).order("updated_at desc").limit(1).to_a
     @previous.first
   end
 
   def subsequent
-    @subsequent ||= begin
-      ArtistCommentaryVersion.where("post_id = ? and updated_at > ?", post_id, updated_at).order("updated_at asc").limit(1).to_a
-    end
+    @subsequent ||= ArtistCommentaryVersion.where("post_id = ? and updated_at > ?", post_id, updated_at).order("updated_at asc").limit(1).to_a
     @subsequent.first
   end
 
   def current
-    @current ||= begin
-      ArtistCommentaryVersion.where("post_id = ?", post_id).order("updated_at desc").limit(1).to_a
-    end
+    @current ||= ArtistCommentaryVersion.where(post_id: post_id).order("updated_at desc").limit(1).to_a
     @current.first
   end