feat: passing multile of the same files in the arguments places a cursor at each position (#12192)

Co-authored-by: Nikita Revenco <154856872+NikitaRevenco@users.noreply.github.com>
Co-authored-by: Michael Davis <mcarsondavis@gmail.com>

helix-term/tests/test/helpers.rs

@@ -345,7 +345,10 @@ impl AppBuilder {
         path: P,
         pos: Option<helix_core::Position>,
     ) -> Self {
-        self.args.files.push((path.into(), pos.unwrap_or_default()));
+        self.args
+            .files
+            .insert(path.into(), vec![pos.unwrap_or_default()]);
+
         self
     }