Do not ask for a calendar of every page

Every page was configured to be rendered as a calendar besides HTML, but there
is no template for that, so Hugo warned on every build:

  WARN  found no layout file for "calendar" for kind "page"

Nothing was lost to the missing template. The only per page calendar template
in the tree, layouts/page/single.ics, sits in the directory for the pages of
the "page" section, which are the imprint, the statutes and similar, while it
renders DTSTART, DTEND and RRULE, which only the pages below
content/veranstaltungen/ have. It has produced nothing for either of them, the
built site contains no per page calendar at all.

Drop the calendar from the outputs of a page. Adding a template instead would
have created a calendar file for every one of the 366 pages, 117 more files
than the site has calendars, nearly all of them empty.

The calendars per section, which the calendar page links to, are configured
separately and keep being generated.

Fixes: c28f04c6e8 ("switch to ics files; make calendars work; fix some minor issues")
Assisted-by: Claude:claude-opus-5
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

config/_default/hugo.toml

@@ -33,7 +33,7 @@ post = "/post/:year/:month/:day/:slug/"
 [outputs]
 home = ["html", "rss", "json"]
 section = ["html", "Calendar", "rss", "xml"]
-page = ["html", "Calendar"]
+page = ["html"]
 
 # Output Formats Configuration
 [outputFormats.Calendar]