git: Fix spurious file creation when staging (#53621)

Neel created

Related to https://github.com/zed-industries/zed/pull/53484. 

This PR fixes a `--` file being created when staging a hunk.

Release Notes:

- N/A

Change summary

crates/git/src/repository.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Detailed changes

crates/git/src/repository.rs 🔗

@@ -1462,7 +1462,7 @@ impl GitRepository for RealGitRepository {
                     log::debug!("indexing SHA: {sha}, path {path:?}");
 
                     let output = git
-                        .build_command(&["update-index", "--add", "--cacheinfo", mode, sha, "--"])
+                        .build_command(&["update-index", "--add", "--cacheinfo", mode, sha])
                         .envs(env.iter())
                         .arg(path.as_unix_str())
                         .output()