#1115: rose edit: count latent section errors

`rose edit` will now display errors for latent namespaces
even when `View Latent Pages` is toggled off.

Latent pages are now always part of the page tree,
but filtered out unless `View Latent Pages` is shown.

This is done by properly including Latent pages in the
tree filtering mechanism, which was set up for this
purpose but not then fully used (only used for
`View All Ignored Pages` and
`View User-Ignored Pages`).

This also fixes a bug in the compulsory macro that
prevented errors from disappearing.

Fix #1115.

@matthewrmshin, please review.