staticcheck.conf: enable ST1000 to check package docs (#20787)

Fix the small number of existing violations of this check, and enable it for
future runs. The fixes needed were:

 - Clean up a few misspelled package names (probably renames).
 - Clean up a few lexical nits ("Package x" instead of "The x package").
 - Add lint directives to some files affected by build tag variance.
 - Add a missing package comment and re-generate the k8s docs.

The lint overrides are a little ugly, but there are only a few places where we
need them, and it's probably worthwhile to enable the check on the rest of the
repo. Rather than replicate the docs around the build tag, I made the lint
diagnotics reference the "correct" file.

Updates #cleanup

Change-Id: I0d97f2f468542af456a0396cf9a023f04f23e436
Signed-off-by: M. J. Fromberger <fromberger@tailscale.com>