Allow #//apple_ref/… links to expand docs too

[pcantrell]

Currently Jazzy generates <a name=…> tags for both USR-style anchors and Dash-style apple_ref anchors:

<a name="/s:6Siesta8ResourceC4loadAA7Request_pyF"></a>
<a name="//apple_ref/swift/Method/load()" class="dashAnchor"></a>
<a class="token token-open" href="#/s:6Siesta8ResourceC4loadAA7Request_pyF">load()</a>

The apple_ref anchors have several advantages: they are human-readable, generally make for shorter links, and (most importantly) are less prone to changes between doc generation cycles and thus make for more stable long-term links from e.g. other documentation.

However, they have a shortcoming in Jazzy: a link of the form Foo.html#//apple_ref/swift/Method/load() currently scrolls to the correct item, but does not expand it.

This PR also expands the item when thus linked, just as Foo.html#/s:6Siesta8ResourceC4loadAA7Request_pyF would.

[pcantrell]

Also, Jazzy should consider symlinking the js files that are identical across the 3 themes instead of copying them.

[johnfairh]

Thanks for this -- when I try it though I can see that the apple_ref links work nicely but the USR ones don't any more, maybe because the next('.token') business doesn't go anywhere if the a[... element actually is the .token?

OK from me to merge this with a fix for that and a changelog update. (I don't know why circle hasn't rebuilt this after your specs update...)

[pcantrell]

Ah, indeed, it turns out that I was looking for nextAll() instead of next(). Good catch!

It’s also apparently possible to do this all in one selector:

$(`a[name="${location.hash.substring(1)}”] ~ .token`)

…but that seems to me too clever by half.

[johnfairh]

Great, thanks.