Update Edit this page at root and error pages

[almndbtr]

Summary

Originally discovered in #102 (comment).

Edit this page was introduced in #102.

However, the Root page (https://wiki.aavegotchi.com/) doesn't have that link. It's worth pointing out that https://wiki.aavegotchi.com/en/index has it, because it's name-spaced under a language.

When navigating to a page that doesn't exist (like https://wiki.aavegotchi.com/does-not-exist), it points to a non-existent page to edit. Instead it should really point to the error page.