CX = check => {
  const reject = (T, ...subs) => check(false, X(T, ...subs));
  return reject;
}
Returns a template literal tag function to fail the provided Checker with details.
The name must be short for ergonomic inline use as in:
```
return checkCondition(...) || (!!check && CX(check)`...`);
```

@param {Checker} check