Remove generated comments from migrations

db/migration/20200208222418_add_defaults_to_annotations.go

@@ -51,6 +51,5 @@ create index annotation_starred
 }
 
 func Down20200208222418(tx *sql.Tx) error {
-	// This code is executed when the migration is rolled back.
 	return nil
 }

db/migration/20200310171621_enable_search_by_albumartist.go

@@ -16,6 +16,5 @@ func Up20200310171621(tx *sql.Tx) error {
 }
 
 func Down20200310171621(tx *sql.Tx) error {
-	// This code is executed when the migration is rolled back.
 	return nil
 }

db/migration/20200319211049_merge_search_into_main_tables.go

@@ -37,6 +37,5 @@ drop table if exists search;
 }
 
 func Down20200319211049(tx *sql.Tx) error {
-	// This code is executed when the migration is rolled back.
 	return nil
 }

db/migration/20200327193744_add_year_range_to_album.go

@@ -75,6 +75,5 @@ create index album_max_year
 }
 
 func Down20200327193744(tx *sql.Tx) error {
-	// This code is executed when the migration is rolled back.
 	return nil
 }

db/migration/20200404214704_add_indexes.go

@@ -25,6 +25,5 @@ create index if not exists media_file_track_number
 }
 
 func Down20200404214704(tx *sql.Tx) error {
-	// This code is executed when the migration is rolled back.
 	return nil
 }

db/migration/20200418110522_reindex_to_fix_album_years.go

@@ -15,6 +15,5 @@ func Up20200418110522(tx *sql.Tx) error {
 }
 
 func Down20200418110522(tx *sql.Tx) error {
-	// This code is executed when the migration is rolled back.
 	return nil
 }