Better Docs for Fetch/Possible Fetch Bug

Fetching a remote branch does not seem to work in any capacity. If it does the docs really need to better document this behavior as it does not seem to work from any way we've tested.

repo.find_remote("origin")
        .unwrap()
        .fetch(&[branch.to_string()], None, None)
        .unwrap();
let fetch_head = repo.find_reference("FETCH_HEAD").unwrap();
let fetch_commit = repo.reference_to_annotated_commit(&fetch_head).unwrap();
let mut reference = repo.find_reference(&format!("refs/heads/{}", branch)).unwrap(); // this line panics which means it did not properly fetch

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { code: -3, klass: 4, message: "reference 'refs/heads/staging' not found" }', leo-commands\src\repo_commands.rs:53:80

Start by reproducing the fetch example and inspect repo_commands.rs at line 53:80, where the missing refs/heads/staging reference is reported. Compare the fetched references with the expected remote-branch behavior. Done means determining whether this is a fetch bug or a documentation gap and documenting or reporting the observed behavior accordingly.