cosmetics: do not swap what ought not to be swapped

src/keypair.rs

@@ -10,8 +10,8 @@ use async_trait::async_trait;
 
 #[async_trait]
 pub trait SSBKeypair {
-    fn from_json(obj: JsonValue) -> Self;
     fn to_json(&self) -> JsonValue;
+    fn from_json(obj: JsonValue) -> Self;
     async fn read_or_generate(path: PathBuf) -> Self;
 }