add ability to hide posts from pagination index

[kvncrw]

this introduced the ability to add hidden: true to the frontmatter.

[parsiya]

Pretty cool feature. Thanks for the pull request. For some reason the condition also hides pages with "hidden" set to "false."

Removing the condition from range and putting it inside and if inside the range works. Seems like the range condition needs to also check if the value is "nil" (which means it's not in the front matter).

{{ $paginator := .Paginate (where .Data.Pages "Type" "post") }}
{{ range $paginator.Pages }}
    {{ if (ne .Params.hidden true) }}
        <article>
           ...
        </article>
    {{ end }}
{{ end }}