Check if the character represented by a given [Unicode code point](https://en.wikipedia.org/wiki/Code_point) is [fullwidth](https://en.wikipedia.org/wiki/Halfwidth_and_fullwidth_forms).
@param codePoint - The [code point](https://en.wikipedia.org/wiki/Code_point) of a character.
@example
```
import isFullwidthCodePoint from 'is-fullwidth-code-point';
isFullwidthCodePoint('谢'.codePointAt(0));
//=> true
isFullwidthCodePoint('a'.codePointAt(0));
//=> false
```
*/
export default function isFullwidthCodePoint(codePoint: number): boolean;