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>

mkdocs.yml

@@ -24,7 +24,6 @@ theme:
     - navigation.tabs
     - navigation.sections
     - navigation.path
-    - toc.integrate
     - navigation.top
     - search.suggest
     - search.highlight