Fix #334: Make links without `href` markable
Commit
be94b559b:
> - Only `<a>` elements with a `href` attribute should be matched, since
> HTML5 allows `<a>` elements to omit `href`:
>
> > If the a element has no href attribute, then the element represents
> > a placeholder for where a link might otherwise have been placed, if
> > it had been relevant, consisting of just the element's contents.
>
> Reference:
> <http://developers.whatwg.org/text-level-semantics.html#the-a-element>
That’s the spec. In the reality, people use all sorts of weird markup.
Some sites (such as StackExchange sites) leave out the `href` property
and use the anchor as a JavaScript-powered button (instead of just using
the `button` element).
This commit reverts the change to link matching in
be94b559b. A side
effect is that sites using links without `href` in compliance with the
spec will get extranous markers for those links. It’s better to show too
many markers than too few, though.