Update README with import feature and Jayvee formatter

Author: georg-schwarz

README.md

@@ -24,11 +24,11 @@ Explore a glimpse of our upcoming features in the following list. This overview
 - ✅ Column-based transformations
 - ✅ Describe blocks via builtin block types in Jayvee
 - ✅ Compose logic of multiple blocks via composite block types
-- ⌛ Multi-file Jayvee to distribute programs over multiple files (see [RFC 0015](./rfc/0015-multi-file-jayvee/0015-multi-file-jayvee.md))
+- ✅ Multi-file Jayvee to distribute programs over multiple files
+- ✅ Jayvee formatter
 - ⌛ Improve the syntax of value types (see [RFC 0014](https://github.com/jvalue/jayvee/pull/409))
-- ⌛ Jayvee formatter
+- ⌛ Reusable libraries (with a package manager)
 - ⌛ Further extractors and sinks
-- 🤔 Reusable libraries (with a package manager)
 - 🤔 Composite value types (with multiple fields)
 - 🤔 Natively support tree data (XML, JSON)
 - 🤔 Valuetypes parsers (to read and write different formats)