Import remaining wiki updates
After Package Maintainer Docs were imported from the wiki
there have been some further wiki updates.
To avoid losing content when wiki pages are replaced
with links to the Package Maintainer Docs,
these updates are imported in this commit.
Some pages were already handled in a preceding commit.
This commit handles the reset.
The "Imported from:" comment is removed
from the top of the pages that are handled
since now that the migration is complete,
that information is not relevant any more.