tests/test-gendoc-de.t

typing: simplify archive.gz writing and drop a few pytype suppressions

I was waiting until 3.8 to use `Literal` to fix this, but there's also the ":"
and "|" characters that are passed along here, meant only for the non-gz archive
types.  But manipulating what the local caller passes is silly- we know we're
writing, so just open it for writing.  As an added bonus, PyCharm stops flagging
the call too (since it doesn't know about pytype suppression comments).

#require docutils gettext

  $ $TESTDIR/check-gendoc de
  checking for parse errors
  Die Dateien werden dem Projektarchiv beim n\xc3\xa4chsten \xc3\x9cbernehmen (commit) hinzugef\xc3\xbcgt. Um dies vorher r\xc3\xbcckg\xc3\xa4ngig zu machen, siehe:hg:`forget`. (esc)
  warning: please have a space before :hg: