small code style fixes

glsl/raymarching.js

    gl.clear(gl.COLOR_BUFFER_BIT);
    var vertexShader = compileShader(gl, gl.VERTEX_SHADER, vertexShaderSrc);
    var fragmentShader = compileShader(gl, gl.FRAGMENT_SHADER, fragmentShaderSrc);
    var fragmentShader = compileShader(gl, gl.FRAGMENT_SHADER, tt.fragmentShaderSrc);
    var program = tt.program = linkShaders(gl, vertexShader, fragmentShader);
    gl.useProgram(program);
  }
  
  window.addEventListener('keydown', function(ev) {
    if (ev.ctrlKey && ev.keyCode == 72) {
    if (ev.ctrlKey && ev.keyCode == 72) { // Ctrl + H
      ev.preventDefault();
      editor.toggle();
    }
  })
  });
} catch (e) {
  displayError(e);
}