fix(css): oops, flat ToC rendering

Adjusted a few ToC and navigation settings to fix flat rendering.
Also removed `toc.integrate`
Fixed margin-left
Altered changelog admonition types
Fixed admonition title rendering bug (overlap)

Signed-off-by: nopeitsnothing <no@anonymousplanet.net>

docs/mirrors/index.md

@@ -3,6 +3,7 @@ title: "Mirrors"
 description: "Every place you can read or download the Hitchhiker's Guide."
 hide:
   - toc
+  - navigation
 schema:
   "@context": https://schema.org
   "@type": Organization