Note an alternative approach to bbolt-only fallback

Not sure why I didn't think of this the first time, rather than the wild
approach I took with all the init functions. Maybe I was hesitant to not
follow the common error handling path, even though it's not relevant.

I still don't want to do this, though. The code is simpler, but the
concept is still hard to explain.

Author: featherbread

internal/store/store.go

@@ -43,6 +43,13 @@ func FactoryFromEnv(ctx context.Context) (Factory, error) {
 	if len(registry.Registry) == 0 {
 		return nil, errors.New("no store backends available in this build")
 	}
+	// If we wanted, we could do this to fall back to bbolt if it were the only
+	// thing linked into the binary:
+	// if len(registry.Registry) == 1 {
+	// 	if bbolt, ok := registry.Registry["bbolt"]; ok {
+	// 		return bbolt.FactoryFromEnv(ctx)
+	// 	}
+	// }
 
 	candidates := make(map[string]registry.Entry)
 	for name, entry := range registry.Registry {