When a kitty window regains text-input focus (e.g. switching back to a
workspace in sway, unminimizing, or unlocking the screen), the
zwp_text_input_v3::enter event is fired. However, text_input_enter()
only called enable + set_content_type without restoring the cursor
rectangle. If the compositor does not re-send wl_keyboard.enter at the
same time, kitty never updates the IME position, causing the popup to
appear at the top-left corner.
Restore the last known cursor rectangle in text_input_enter() so the
IME popup immediately appears at the correct position.
