JS Style Guide: Add rules for constructor invocation

Ref https://github.com/jquery/jquery/pull/1856#issuecomment-65346516

These reflect my personal preference for explicit clarity (especially around whitespace-preceding keyword operators) and could easily be changed; I just want to get some clear guidelines published.
Um...  Don't we need spaces inside the parens around both of these if we do require them?

```js
detachedMode = ( new TemplateFactory( settings ) ).nodeType === 11;
match = ( new RegExp( pattern ) ).exec( input );
```