Syntax for RegExp literals

JS has the following syntax for RegExp literals:

```js
const myRegExp = /ab+c/;
```

In ReScript, this would currently be expressed as

```rescript
let myRegExp = %re("/ab+c/")
```

It would be nice if ReScript also had dedicated syntax for regexp literals, if possible identical to the JS version:

```rescript
let myRegExp = /ab+c/
```