Fix clamping scroll in certain cases.

.clamp(min, max) requires that min < max. In some cases
first + scrolloff > last - scrolloff and we would panic.

helix-term/src/commands.rs

@@ -462,10 +462,9 @@ fn scroll(cx: &mut Context, offset: usize, direction: Direction) {
     .min(doc_last_line);
 
     // clamp into viewport
-    let line = (view.first_line + cursor_off).clamp(
+    let line = (view.first_line + cursor_off)
-        view.first_line + scrolloff,
+        .max(view.first_line + scrolloff)
-        last_line.saturating_sub(scrolloff),
+        .min(last_line.saturating_sub(scrolloff));
-    );
 
     let text = doc.text().slice(..);
     let pos = pos_at_coords(text, Position::new(line, cursor.col)); // this func will properly truncate to line end