R1:03abde0b257f

Fix Diviner links to articles by title

Summary:
Ref T988. This fixes the biggest current problem with Diviner, which is dead links to articles.

In the new Diviner, articles can have both a "name" (derived from the file name, and used in the URI) and a "title" (optional, specified explicitly). For example, we have one document with the name "feedback" and the title "Give Feedback! Get Support!".

On disk, we want to use the name for the actual file where the text lives ("feedback.diviner"). We also want…