Convert many match/if expressions to let-else

crates/handlers/src/oauth2/authorization/complete.rs

@@ -107,9 +107,7 @@ pub(crate) async fn get(
     let callback_destination = CallbackDestination::try_from(&grant)?;
     let continue_grant = PostAuthAction::continue_grant(grant.id);
 
-    let session = if let Some(session) = maybe_session {
-        session
-    } else {
+    let Some(session) = maybe_session else {
         // If there is no session, redirect to the login screen, redirecting here after
         // logout
         return Ok((cookie_jar, mas_router::Login::and_then(continue_grant).go()).into_response());

crates/handlers/src/oauth2/consent.rs

@@ -166,9 +166,7 @@ pub(crate) async fn post(
         .ok_or(RouteError::GrantNotFound)?;
     let next = PostAuthAction::continue_grant(grant_id);
 
-    let session = if let Some(session) = maybe_session {
-        session
-    } else {
+    let Some(session) = maybe_session else {
         let login = mas_router::Login::and_then(next);
         return Ok((cookie_jar, login.go()).into_response());
     };

crates/handlers/src/oauth2/introspection.rs

@@ -154,9 +154,7 @@ pub(crate) async fn post(
         .verify(&http_client_factory, &encrypter, method, &client)
         .await?;
 
-    let form = if let Some(form) = client_authorization.form {
-        form
-    } else {
+    let Some(form) = client_authorization.form else {
         return Err(RouteError::BadRequest);
     };