Document crate features

README.md

@@ -61,6 +61,14 @@ let serde_bytes = serde_json::to_vec(&desc)?;
 let borsh_bytes = borsh::to_vec(&desc)?;
 ```
 
+## Features
+
+| Feature | Default? | Description |
+| :--- | :---: | :--- |
+| `address` | ✓ | Adds Bitcoin address and `ScriptBuf` functionality |
+| `borsh` | | Adds descriptor serialization and deserialization via [`borsh`](https://borsh.io) |
+| `serde` | ✓ | Adds descriptor serialization and deserialization via [`serde`](https://serde.rs) |
+
 ## Rationale
 
 There doesn't exist any general standard way to encode arbitrary relay-safe