Naming, layout and comments: descriptive full-word names, one item per line in wrapped calls and literals, and doc comments on exported names

Short and single-letter names in application code become full words (tests
keep theirs). Wrapped calls, signatures and composite literals put one item
per line, and one-line function bodies are expanded. Exported names and
groups of constants get doc comments, and comments refer to the renamed
identifiers.

internal/store/migrate_test.go

@@ -16,6 +16,7 @@ import (
 // Run with: go test -tags sqlite_fts5 ./...
 
 func tempDBPath(t *testing.T) string {
+	t.Helper()
 	return filepath.Join(t.TempDir(), "migrate.db")
 }
 
@@ -25,7 +26,9 @@ func newMigrator(t *testing.T) (*goose.Provider, *sql.DB) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	t.Cleanup(func() { db.Close() })
+	t.Cleanup(func() {
+		db.Close()
+	})
 	m, err := store.NewMigrator(db)
 	if err != nil {
 		t.Fatal(err)
@@ -93,7 +96,8 @@ func TestOpenRejectsNewerSchema(t *testing.T) {
 	}
 	defer db.Close()
 	if _, err := db.Exec(
-		`INSERT INTO goose_db_version (version_id, is_applied) VALUES (9999, 1)`); err != nil {
+		`INSERT INTO goose_db_version (version_id, is_applied) VALUES (9999, 1)`,
+	); err != nil {
 		t.Fatal(err)
 	}
 
@@ -268,7 +272,8 @@ func TestNewerDatabaseIsRefused(t *testing.T) {
 		t.Fatal(err)
 	}
 	if _, err := db.Exec(
-		`INSERT INTO goose_db_version (version_id, is_applied) VALUES (9999, 1)`); err != nil {
+		`INSERT INTO goose_db_version (version_id, is_applied) VALUES (9999, 1)`,
+	); err != nil {
 		t.Fatal(err)
 	}