[dom] Missing spaces in rendered spec HTML (#65)

In a few places in the bikeshed source, this:
```html
<a>:scope element</a> <a>context object</a>
```
is getting compiled to the following HTML (do a View Source on https://dom.spec.whatwg.org/):
```html
<a data-link-type="dfn" href="https://drafts.csswg.org/selectors-4/#scope-element">:scope element</a><a data-link-type="dfn" href="#context-object">context object</a>
```

Note the lack of a space between the two resulting `<a>`s.

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Reply to this email directly or view it on GitHub:
https://github.com/whatwg/dom/issues/65