Fix commting with one stack

There was an issue where the parents of the workspace commit are not always up to date.

While this is something we seperatly need to fix, it also makes sense to move to something more reliable. (And also reduce the amount of forking in the function). As such, I've switched it to always use the multi-branch case

Author: Caleb-T-Owens

crates/but-workspace/src/commit_engine/reference_frame.rs

@@ -22,14 +22,6 @@ impl ReferenceFrame {
     ) -> anyhow::Result<Self> {
         let head_id = repo.head_id()?;
         let workspace_commit = head_id.object()?.into_commit().decode()?.to_owned();
-        if workspace_commit.parents.len() < 2 {
-            return Ok(crate::commit_engine::ReferenceFrame {
-                workspace_tip: Some(head_id.detach()),
-                // The workspace commit is never the tip
-                #[allow(clippy::indexing_slicing)]
-                branch_tip: Some(workspace_commit.parents[0]),
-            });
-        }
 
         let cache = repo.commit_graph_if_enabled()?;
         let mut graph = repo.revision_graph(cache.as_ref());