Make gps list show played stack in rebase

Make gps list show played stack in rebase so that we can see the patches
in the stack that have already been played, including if they were
squashed, etc. and their associated meta data as well as the next todos
to be run as part of the rebase.

This relates to issues #273 and #280.

[changelog]
added: gps list support during rebases

<!-- ps-id: 920cba9f-581b-4c57-8b41-70c058e5d39f -->

src/ps/mod.rs

@@ -62,13 +62,19 @@ impl std::error::Error for PatchStackError {
 
 pub fn get_patch_stack(repo: &git2::Repository) -> Result<PatchStack<'_>, PatchStackError> {
     let head_ref = repo.head()?;
-    let upstream_branch_name_buf = head_ref
-        .name()
-        .ok_or(PatchStackError::HeadNoName)
-        .and_then(|head_branch_name| {
-            repo.branch_upstream_name(head_branch_name)
-                .map_err(PatchStackError::GitError)
-        })?;
+    let repo_gitdir_path = repo.path();
+
+    let head_branch_name = match git::in_rebase(repo_gitdir_path) {
+        true => git::in_rebase_head_name(repo_gitdir_path)
+            .unwrap()
+            .trim()
+            .to_string(),
+        false => git::get_current_branch(repo).ok_or(PatchStackError::HeadNoName)?,
+    };
+
+    let upstream_branch_name_buf = repo
+        .branch_upstream_name(&head_branch_name)
+        .map_err(PatchStackError::GitError)?;
     let upstream_branch_name = upstream_branch_name_buf
         .as_str()
         .ok_or(PatchStackError::UpstreamBranchNameNotFound)?;

src/ps/private/git.rs

@@ -50,7 +50,6 @@ mod git_error;
 #[cfg(feature = "backup_cmd")]
 mod hash_object_write;
 mod in_rebase;
-mod in_rebase_done_todos;
 mod in_rebase_head_name;
 mod in_rebase_onto;
 mod in_rebase_todos;
@@ -87,7 +86,6 @@ pub use git_error::*;
 #[cfg(feature = "backup_cmd")]
 pub use hash_object_write::*;
 pub use in_rebase::*;
-pub use in_rebase_done_todos::*;
 pub use in_rebase_head_name::*;
 pub use in_rebase_onto::*;
 pub use in_rebase_todos::*;