Update population_rank

[pathmapper]

According to
https://github.com/whosonfirst/whosonfirst-properties/blob/fe0b2e2f314502744ba05d0d6ada9ade9d53ef10/properties/wof/README.md#population_rank
population ranks 15, 16, 17, 18 are missing in docs
https://whosonfirst.org/docs/properties/wof/#population_rank

[nvkelso]

Thanks for pointing that out, we should fix it! The original list was focused on locality only, the new list includes other placetypes like country.

I suspect this is because the Makefile needs to be updated with docs targets, looks like those are MIA now. Generally we use a build process to gather content from other repos instead of manually editing the docs here.

• https://github.com/whosonfirst/whosonfirst-www/blob/master/Makefile#L59

[pathmapper]

@nvkelso thanks, so closing here and open an issue instead, right?

Sorry, should have read https://github.com/whosonfirst/whosonfirst-www#example-editing-a-page-from-github

[nvkelso]

Yes, closing in favor of #60.