Fix edge cases for /* @once */ static marker

[titoBouzout]

Fixes a couple of edge cases when using /* @once */:

1. @once now works in nested objects, <div style={/* @once */ { width: props.width, height: props.height }} /> - Problem was that when the @once expression was found, it was removed, so any nested object became dynamic again.
2. works with object properties as <div style={/* @once */prop.style}/> - problem was that classList and style were hardcoded to be dynamic, not respecting the @once mark.
3. works with spreads <div { /* @once */ ... props}/> but only top level - this was just never considered.

A note about spreads, consider the following:

const template28 = (
  <div {/* @once */ ...propsSpread} data-static={/* @once */ color()} data-dynamic={color()} />
);

What should happen is that propsSpread and color() for data-static should be static.

If we look at the generated code, it becomes more evident that the issue is mergeProps rather than spread, as spread has no option but to add the effect for the props that are actually dynamic.

const template28 = (() => {
  var _el$34 = _tmpl$3();
  _$spread(
    _el$34,
    _$mergeProps(propsSpread, {
      get ["data-dynamic"]() {
        return color();
      },
      "data-static": color()
    }),
    false,
    false
  );
  return _el$34;
})();

As a compromise, the spread value is now spreaded (when used with @once), meaning that mergeProps won't track the top level of the object. If access happens in any sub-objects then it will track. This solution is simple enough and possibly covers the immediate expectation.

const template28 = (() => {
  var _el$34 = _tmpl$3();
  _$spread(
    _el$34,
    _$mergeProps({ ...propsSpread }, {
      get ["data-dynamic"]() {
        return color();
      },
      "data-static": color()
    }),
    false,
    false
  );
  return _el$34;
})();

Related:

• /* @once */ seems to work only for first child of object #252
• Ability to set certain properties / attributes as always static #343
• Using imported object for style attribute is reevaluated if other attribute uses updated signal solidjs/solid#1938
• https://discord.gg/solidjs
• https://discord.com/channels/722131463138705510/751355413701591120/1391981719128637523
• https://discord.com/channels/722131463138705510/1361436114484985987/1392936591999373343

[titoBouzout]

cc @lxsmnsyc @edemaine