Git UI papercuts (#26316)

Release Notes:

- Git Beta: added `git:Add` as an alias for the existing `git::Diff`
- Git Beta: Fixed a bug where the 'generate commit message' keybinding
wasn't working.
- Git Beta: Made the empty project diff state a little more helpful with
a button to push, and a button to close the item.

crates/git_ui/src/commit_modal.rs

@@ -2,7 +2,7 @@
 
 use crate::branch_picker::{self, BranchList};
 use crate::git_panel::{commit_message_editor, GitPanel};
-use git::Commit;
+use git::{Commit, GenerateCommitMessage};
 use panel::{panel_button, panel_editor_style, panel_filled_button};
 use ui::{prelude::*, KeybindingHint, PopoverMenu, Tooltip};
 
@@ -372,6 +372,11 @@ impl Render for CommitModal {
             .key_context("GitCommit")
             .on_action(cx.listener(Self::dismiss))
             .on_action(cx.listener(Self::commit))
+            .on_action(cx.listener(|this, _: &GenerateCommitMessage, _, cx| {
+                this.git_panel.update(cx, |panel, cx| {
+                    panel.generate_commit_message(cx);
+                })
+            }))
             .on_action(
                 cx.listener(|this, _: &zed_actions::git::Branch, window, cx| {
                     toggle_branch_picker(this, window, cx);