Grammatical disambiguation (#504)

Prevents interpretation as “JSX is closer to JavaScript than HTML is”. The latter is obviously true, but the apparent meaning is the former, which is less obvious.

content/docs/introducing-jsx.md

@@ -93,7 +93,7 @@ Don't put quotes around curly braces when embedding a JavaScript expression in a
 
 >**Warning:**
 >
->Since JSX is closer to JavaScript than HTML, React DOM uses `camelCase` property naming convention instead of HTML attribute names.
+>Since JSX is closer to JavaScript than to 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).