gets a `depends_simple` built up that contains link dependencies for
*every* page in the wiki. A very bloaty way to represent the dependency!
-Per [[dependency_types]], `link(done)` only needs to list in
+Per [[todo/dependency_types]], `link(done)` only needs to list in
`depends_simple` the pages that currently match. If a page is modified
to add the link, the regular dependency calculation code notices that
a new page matches. If a page that had the link is modified to remove it,