git: Refine diff hunk controls visuals (#26317)

You may need to zoom in hard to see this 😅 but the main addition of this
PR is just ensuring there's also horizontal border instead of just on
the bottom. Also added some box-shadow here to make it pop out of the
diff a bit more.

| Before | After |
|--------|--------|
| ![CleanShot 2025-03-08 at 12  37
40@2x](https://github.com/user-attachments/assets/98e0329e-646f-4455-89fa-3f6ec1211361)
| ![CleanShot 2025-03-08 at 12  36
40@2x](https://github.com/user-attachments/assets/7f667e65-5b72-4156-b0ec-2b162eb76f2f)
|

Release Notes:

- N/A

crates/editor/src/element.rs

@@ -8896,14 +8896,16 @@ fn diff_hunk_controls(
         .h(line_height)
         .mr_1()
         .gap_1()
-        .px_1()
+        .px_0p5()
         .pb_1()
+        .border_x_1()
         .border_b_1()
         .border_color(cx.theme().colors().border_variant)
         .rounded_b_lg()
         .bg(cx.theme().colors().editor_background)
         .gap_1()
         .occlude()
+        .shadow_md()
         .child(if status.has_secondary_hunk() {
             Button::new(("stage", row as u64), "Stage")
                 .alpha(if status.is_pending() { 0.66 } else { 1.0 })
@@ -8960,7 +8962,7 @@ fn diff_hunk_controls(
                 })
         })
         .child(
-            Button::new("discard", "Restore")
+            Button::new("restore", "Restore")
                 .tooltip({
                     let focus_handle = editor.focus_handle(cx);
                     move |window, cx| {