ElyMark: navigation tested through the whole window (C14.8)

desk::open_in takes the data folder, so gpui tests start ElyMark in a
temp folder: open, outline, jump, recent list, tabs, folder listing.
The web page strings, left from C14.5, go.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/ely-mark/src/side.rs

@@ -253,7 +253,7 @@ impl Side {
                 let Some(heading) = key.parse::<usize>().ok().and_then(|at| headings.get(at)) else {
                     return log::error!("mark: the outline chose no heading");
                 };
-                // Keys go to the document, at the heading.
+                // The heading in view, the caret on it.
                 let line = heading.line;
                 view.update(cx, |view, cx| view.reveal(line, window, cx));
             })