hide help if escape is pressed

glsl/docs.js

@@ -131,5 +131,9 @@ document.body.appendChild(docsContainerEl);
window.addEventListener("keydown", function(ev) {
  if (ev.ctrlKey && ev.keyCode == 72) { // Ctrl-h
    handleToggle(ev);
  } else if (ev.keyCode == 27) { // Escape
    if (location.hash == "#docs") {
      handleToggle(ev);
    }
  }
});