refactor: enable clippy::manual_is_variant_and

src/config.rs

@@ -591,8 +591,7 @@ impl Context {
             .get_config(key)
             .await?
             .and_then(|s| s.parse::<i32>().ok())
-            .map(|x| x != 0)
-            .unwrap_or_default())
+            .is_some_and(|x| x != 0))
     }
 
     /// Returns true if movebox ("DeltaChat" folder) should be watched.

src/imap.rs

@@ -2152,11 +2152,10 @@ pub(crate) async fn prefetch_should_download(
     let accepted_contact = origin.is_known();
     let is_reply_to_chat_message = get_prefetch_parent_message(context, headers)
         .await?
-        .map(|parent| match parent.is_dc_message {
+        .is_some_and(|parent| match parent.is_dc_message {
             MessengerMessage::No => false,
             MessengerMessage::Yes | MessengerMessage::Reply => true,
-        })
-        .unwrap_or_default();
+        });
 
     let show_emails =
         ShowEmails::from_i32(context.get_config_int(Config::ShowEmails).await?).unwrap_or_default();

src/lib.rs

@@ -14,7 +14,8 @@
     clippy::unused_async,
     clippy::explicit_iter_loop,
     clippy::explicit_into_iter_loop,
-    clippy::cloned_instead_of_copied
+    clippy::cloned_instead_of_copied,
+    clippy::manual_is_variant_and
 )]
 #![cfg_attr(not(test), forbid(clippy::indexing_slicing))]
 #![cfg_attr(not(test), forbid(clippy::string_slice))]