Replace "caveat" with "warning"?

[kaycebasques]

Nice docs :)

Just a suggestion to replace "caveat", as seen here in Introducing JSX

>**Caveat:**
>
>Since JSX is closer to JavaScript than HTML, React DOM uses `camelCase` property naming convention instead of HTML attribute names.
>
>For example, `class` becomes [`className`](https://developer.mozilla.org/en-US/docs/Web/API/Element/className) in JSX, and `tabindex` becomes [`tabIndex`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/tabIndex).

with a less-fancy / more straightforward word such as "warning"

[bvaughn]

Good suggestion. Would you be interested in submitting a PR for this?

[bvaughn]

Fixed via PR #163