style: use Self to avoid unnecessary repetition (#3396)

axum-extra/src/extract/cookie/mod.rs

@@ -321,13 +321,13 @@ mod tests {
     }
 
     impl FromRef<AppState> for Key {
-        fn from_ref(state: &AppState) -> Key {
+        fn from_ref(state: &AppState) -> Self {
             state.key.clone()
         }
     }
 
     impl FromRef<AppState> for CustomKey {
-        fn from_ref(state: &AppState) -> CustomKey {
+        fn from_ref(state: &AppState) -> Self {
             state.custom_key.clone()
         }
     }

axum-extra/src/extract/cookie/private.rs

@@ -136,7 +136,7 @@ where
             key,
             _marker: _,
         } = PrivateCookieJar::from_headers(&parts.headers, key);
-        Ok(PrivateCookieJar {
+        Ok(Self {
             jar,
             key,
             _marker: PhantomData,

axum-extra/src/extract/cookie/signed.rs

@@ -153,7 +153,7 @@ where
             key,
             _marker: _,
         } = SignedCookieJar::from_headers(&parts.headers, key);
-        Ok(SignedCookieJar {
+        Ok(Self {
             jar,
             key,
             _marker: PhantomData,