Correct a bunch of incorrect/outdated references (#2457)

- Babel 7 has a whole different module API
- Traceur is basically dead
- JSX != HTML
- Some bits are just obvious from context what they are
- ES6 docs shouldn't be auto-installing JSX support
- Also, I decided it was worth clearing up some misleading docs in
  surrounding areas.

docs/route.md

@@ -743,7 +743,7 @@ In certain situations, you may find yourself needing to interoperate with anothe
 
 Here's an example with React:
 
-```javascript
+```jsx
 class Child extends React.Component {
 	constructor(props) {
 		super(props)