Rust 1.78 (#11314)

Notable things I've had to fix due to 1.78:
- Better detection of unused items
- New clippy lint (`assigning_clones`) that points out places where assignment operations with clone rhs could be replaced with more performant `clone_into`
Release Notes:

- N/A

crates/zed/src/reliability.rs

@@ -524,7 +524,7 @@ async fn upload_previous_crashes(
             }
 
             if uploaded < filename {
-                uploaded = filename.clone();
+                uploaded.clone_from(&filename);
                 KEY_VALUE_STORE
                     .write_kvp(LAST_CRASH_UPLOADED.to_string(), filename)
                     .await?;