Support Custom Elements in JSX

[kamituel]

It is not currently possible to use a Reason's JSX syntax to create a custom element. E.g. this won't compile:

/* JavaScript code executed somewhere before our Reason's JSX */
customElements.define("example-component", ...);

/* Reason JSX */
<example-component></example-component>

It doesn't compile because of a hyphen - in the component name. However, this hyphen is actually mandatory. Without the hyphen, .define() throws. As MDN puts it:

Name for the new custom element. Note that custom element names must contain a hyphen.

(source).

Also note that JSX in JavaScript does allow hyphens and thus works with custom elements.

Thus I think Reason's JSX ppx should handle this case.