gui_toolkit 0.53.0

Added

• Find in page (ui.find, ui.find_matches, ui.find_count, ui.find_set_current): the occurrences of a needle in the text the interface shows (labels, wrapped paragraphs, rich text, a match across the runs of a paragraph), found after each layout in reading order with their rectangles whether on screen or scrolled away, painted behind the text (theme entries "find_match background", "find_current background"); case ignored. The application owns the field and the navigation.