Simple example for LineString containing a Point fails

[frewsxcv]

From @michaelkirk's comment here:

This example I contrived fails:

use geo::algorithm::contains::Contains;
use geo::{LineString, Point};

let line_string = LineString::from(vec![(0., 0.), (3., 3.)]);
let point_on_line = Point::new(1., 1.);
assert!(line_string.contains(&point_on_line)); // <- 💥 currently fails

I don't think this was a change in behavior with this PR, but at least one point of comparison, postgis, agrees that we should change it so that my example passes:

psql> SELECT ST_Contains(
  ST_MakeLine(ST_MakePoint(0,0), ST_MakePoint(3,3)),
  ST_MakePoint(1,1)
);

st_contains 
-------------
 t

[frewsxcv]

This may be related to #415