Revert "chore: Bump Rust version to 1.77 (#9631)" (#9658)

This reverts commit 6184278faf.

We can't upgrade to Rust 1.77 until there are Rust 1.77 Docker images
available
(https://github.com/docker-library/official-images/pull/16457).


Release Notes:

- N/A

crates/journal/src/journal.rs

@@ -94,7 +94,6 @@ pub fn new_journal_entry(app_state: Arc<AppState>, cx: &mut WindowContext) {
         std::fs::create_dir_all(month_dir)?;
         OpenOptions::new()
             .create(true)
-            .truncate(false)
             .write(true)
             .open(&entry_path)?;
         Ok::<_, std::io::Error>((journal_dir, entry_path))