Fix random HMR failures

Hot module reloading would freeze as soon as it encountered any
compilation error. So when introducing a compilation error (e.g., a
missing semicolon for a CSS rule) and then saving, the HMR is just
frozen. Even if you fix the compilation error by adding the semicolon,
it remains frozen, meaning that I often think that my CSS is wrong, even
when it's not.

What this line of code does is just does a refresh of the page whenever
a change is encountered. Nothing fancy, and it means that it works
predictably.

Similar issue but related to Elm instead of CSS:
parcel-bundler/parcel#6124

index.js

@@ -3,6 +3,13 @@ import {CheckerLegacy} from "./checker.js";
 import {Bar, Point, Position} from "./position.js";
 import Player from "./player.js";
 
+// https://github.com/parcel-bundler/parcel/pull/443#issuecomment-354583425
+if (module.hot) {
+ module.hot.accept(function () {
+ window.location.reload();
+ });
+}
+
 /**
  * https://rwaldron.github.io/proposal-math-extensions/#sec-math.clamp
  *