Git tweaks (#28791)

Release Notes:

- git: Add a `git_panel.sort_by_path` setting to mix untracked/tracked
files in the diff list.
- git: Remove the "•" placeholder for "Tracked". The commit button says
"Commit Tracked" still by default, and this was misinterpreted to mean
"partially staged". Hovering over the button will show you which files
are tracked (in addition to the yellow square-with-a-dot-in-it).
- Increase the default value of `expand_excerpt_lines` from 3 to 5. This
makes it faster to see more context in the git diff view.

---------

Co-authored-by: Birk Skyum <birk.skyum@pm.me>
Co-authored-by: Peter Tripp <peter@zed.dev>

crates/git_ui/src/git_panel_settings.rs

@@ -64,6 +64,12 @@ pub struct GitPanelSettingsContent {
     ///
     /// Default: main
     pub fallback_branch_name: Option<String>,
+
+    /// Whether to sort entries in the panel by path
+    /// or by status (the default).
+    ///
+    /// Default: false
+    pub sort_by_path: Option<bool>,
 }
 
 #[derive(Deserialize, Debug, Clone, PartialEq)]
@@ -74,6 +80,7 @@ pub struct GitPanelSettings {
     pub status_style: StatusStyle,
     pub scrollbar: ScrollbarSettings,
     pub fallback_branch_name: String,
+    pub sort_by_path: bool,
 }
 
 impl Settings for GitPanelSettings {