markdown doesn't render beyond index.md

Keybase GUI Version: 4.0.0-20190507193726+6614a49937

If I place a link in index.md to another markdown file, the link is followed, but the markdown isn't rendered (boo!)

Start by reproducing the issue in the Keybase GUI with an index.md link to another Markdown file, then trace the GUI's Markdown rendering entry point. Done means the linked Markdown file renders as Markdown rather than appearing as unrendered text.

Written by the indexing model from the issue text.