doc: add number for note on git version in list of CTCP replies (user's guide)
core: add missing period in /help upgrade
doc: fix some punctuation errors in translations
irc: fix error message on /invite without arguments (bug #39272)
doc: fix typo in plugin API reference
core: update german translations
core: add completion "-quit" for command /upgrade

A "-dummy" option has been added too, just to prevent accidental completion with
"-quit" (which is the first option completed).

Thanks to stfn for initial patch.
Merge branch 'master' of git://git.sv.gnu.org/weechat

Conflicts:
	po/ja.po
translation: update
Merge branch 'master' of git://git.sv.gnu.org/weechat

Conflicts:
	po/ja.po
translation: update