fix minified spaces and slice bundle size

[bartveneman]

• minify spaces in value lists, closes List item spacing not minified #38
• reduce bundle size by re-using SPACE = ' ' and a bunch more strings

before

       1891 B: format.cjs.gz
       1699 B: format.cjs.br
       1303 B: format.modern.js.gz
       1199 B: format.modern.js.br
       1864 B: format.module.js.gz
       1666 B: format.module.js.br
       1940 B: format.umd.js.gz
       1748 B: format.umd.js.br

 4294  format.cjs
18306  format.cjs.map
 3142  format.modern.js
17615  format.modern.js.map
 4203  format.module.js
18312  format.module.js.map
 4500  format.umd.js
18309  format.umd.js.map
  762  index.d.ts

after

       1411 B: format.cjs.gz
       1282 B: format.cjs.br
       1359 B: format.modern.js.gz
       1240 B: format.modern.js.br
       1375 B: format.module.js.gz
       1258 B: format.module.js.br
       1485 B: format.umd.js.gz
       1354 B: format.umd.js.br

  3369  format.cjs
 19815  format.cjs.map
  3217  format.modern.js
 19796  format.modern.js.map
  3282  format.module.js
 19827  format.module.js.map
  3575  format.umd.js
 19818  format.umd.js.map
   762  index.d.ts

the 1kB size decrease is because we're no longer using for-loops which caused the inclusion of this huge polyfill:

function r(e, r) {
  (null == r || r > e.length) && (r = e.length);
  for (var t = 0, n = new Array(r); t < r; t++) n[t] = e[t];
  return n;
}
function t(e, t) {
  var n =
    ("undefined" != typeof Symbol && e[Symbol.iterator]) || e["@@iterator"];
  if (n) return (n = n.call(e)).next.bind(n);
  if (
    Array.isArray(e) ||
    (n = (function (e, t) {
      if (e) {
        if ("string" == typeof e) return r(e, t);
        var n = Object.prototype.toString.call(e).slice(8, -1);
        return (
          "Object" === n && e.constructor && (n = e.constructor.name),
          "Map" === n || "Set" === n
            ? Array.from(e)
            : "Arguments" === n ||
              /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)
            ? r(e, t)
            : void 0
        );
      }
    })(e)) ||
    (t && e && "number" == typeof e.length)
  ) {
    n && (e = n);
    var a = 0;
    return function () {
      return a >= e.length ? { done: !0 } : { done: !1, value: e[a++] };
    };
  }
  throw new TypeError(
    "Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."
  );
}