Does not with with i18n when using folder structure

[nahuhh]

Related: #33
The related issue above is when using suffix.

This issue is to point out that folder structure is broken as well.

fails:

- plugins:
  - redirects:
      redirect_maps:
        'running-node/open-node-tor-onion.md': 'running-node/systemd.md'

it succeeds if i18n is disabled.
With folder structure, these files are located in folders like en/running-node/open-node-tor-onion.md

this plugin should respect
running-node/open-node-tor-onion.md (same as the declaration in the nav) and/or perhaps accurately use relative redirects like

 'running-node/open-node-tor-onion.md': '../running-node/systemd.md'