T19 round 1 fixes

- merges keep each line's ending and the last newline; resolve keeps every other byte
- the split view numbers each side from its own file
- hunk headers come from similar's UnifiedHunkHeader: an empty side starts before its range
- the commit subject counter sits in the input's suffix
- clipped code rows in diffs, merges, blame and review set their line height
- gallery: scripted split view and a long subject

src/git/changes.rs

@@ -333,9 +333,8 @@ impl RenderOnce for CommitInput {
                 }
             })
             .child(
-                div().relative().child(Input::new(&self.subject)).child(
-                    tabular(div().absolute().top_2().right_2().text_color(count))
-                        .child(format!("{length}/{}", SUBJECT.0)),
+                Input::new(&self.subject).suffix(
+                    tabular(div().text_color(count)).child(format!("{length}/{}", SUBJECT.0)),
                 ),
             )
             .child(Input::new(&self.body))