fn elided<'a>(text: &'a str, rows: &[Row], room: WorldPx) -> Cow<'a, str>Expand description
text, laid out in rows, cut to the first TEXT_BOX_MAX_ROWS of them.
The last row kept ends in an ellipsis, losing the glyphs that would leave
it no room for one. A Row holds one glyph per character, less the
newline that ends it.