Fix single line edit prediction detection (#23456)

#23411 introduced an "Accept" callout for single line edits, but the
logic to detect them was incorrect causing it to trigger for multiline
insertions, this PR fixes that.

Release Notes:

- N/A

crates/gpui/src/elements/div.rs

@@ -1211,7 +1211,6 @@ impl Element for Div {
             state.child_bounds = Vec::with_capacity(request_layout.child_layout_ids.len());
             state.bounds = bounds;
             let requested = state.requested_scroll_top.take();
-            // TODO az
 
             for (ix, child_layout_id) in request_layout.child_layout_ids.iter().enumerate() {
                 let child_bounds = cx.layout_bounds(*child_layout_id);