terminal: fix moving selection on history changing

src/terminal/search/screen.zig

@@ -493,6 +493,10 @@ pub const ScreenSearch = struct {
             // in our history (fast path)
             if (results.items.len == 0) break :history;
 
+            // The number added to our history. Needed for updating
+            // our selection if we have one.
+            const added_len = results.items.len;
+
             // Matches! Reverse our list then append all the remaining
             // history items that didn't start on our original node.
             std.mem.reverse(FlattenedHighlight, results.items);
@@ -505,7 +509,7 @@ pub const ScreenSearch = struct {
             if (self.selected) |*m| selected: {
                 const active_len = self.active_results.items.len;
                 if (m.idx < active_len) break :selected;
-                m.idx += results.items.len;
+                m.idx += added_len;
 
                 // Moving the idx should not change our targeted result
                 // since the history is immutable.