Fix inter-page links #28

The previous Seattle Trac wiki pages now live in this repo, and are kept in Markdown format (see #4). Some of the converted pages still contain wiki: links that we could not automatically convert. We need to find and update these links!

Here's how to generate a file listing containing old wiki links, courtesy of @lukpueh:

grep -lr --include="*.md" "wiki:\|\.wiki" .

Looking forward to your PRs!