Steps to reproduce:
* Make sure LivePreview is activated in https://de.wikipedia.org/wiki/Spezial:Einstellungen#mw-prefsection-editing
* Start creating a new page in German user interface language. For example https://de.wikipedia.org/w/index.php?title=New_page&action=edit&uselang=de
** The firstHeading contains //„New page“ – Erstellen//
* Click on //Vorschau Zeigen//.
** The firstHeading contains //{{„}}{{{1|$1}}}{{“}} – Erstellen//
** Expected result: //„New page“ – Erstellen//
The reason is in https://de.wikipedia.org/wiki/MediaWiki:Creating. It contains
```
{{„}}{{{1|$1}}}{{“}} – Erstellen
```
and `mw.msg` from https://gerrit.wikimedia.org/r/182780 and https://gerrit.wikimedia.org/r/187710 does not support expansion of templates and the template are not on client side.
The best solution would be a possibility to use messages that gets expanded on server side.
Currently
'messages' => array(
'creating',
)
sets `mw.messages.set( 'creating', '{{„}}{{{1|$1}}}{{“}} – Erstellen' )`. For expanded messages a new ResourceLoader module would be necessary:
'expandedmessages' => array(
'creating',
)
sets `mw.messages.set( 'creating', '„$1“ – Erstellen' )`.