Fix example 183 lat/lon values to Numbers, not String

[gobengo]

Resolves #446

[kaleb]

Shouldn't this have been fixed in the file https://github.com/w3c/activitystreams/blob/master/test/vocabulary-ex183-jsonld.json instead? And the re-gen the php @gobengo ?

[gobengo]

@kaleb I don't believe the index.html is generated from those example json files.

Also have no idea why @evanp closed this. Still seems right to have those be numbers and not strings. All the other uses of the latitude/longitude properties in the vocabulary document use numbers.

[dontcallmedom]

The problem was documented in the errata from what I can see:
3b5df7a

That said, fixing the main HTML file itself would still make sense I think, so re-opening the pull request (at the very least, documenting why it should be closed would be better)