Function is_self_contained 

pub fn is_self_contained(line: &str) -> bool

True when line leaves no colour or attribute switched on at its end.

Every line returned by the renderers satisfies this, which is what lets lines be printed, indented or boxed independently of each other.

use shellgame::ui::text::is_self_contained;

assert!(is_self_contained("\x1b[1mbold\x1b[0m and plain"));
assert!(!is_self_contained("\x1b[1mbold"));