(bug 70596) fix i18n.twtranslate call

- synchronize with core
- use site.code instead of site.lang (which is the same in compat)
- use generic {{delete}}, maybe this should be localized in next step

Change-Id: I544088aea6320805d20210047aec95b466e05aae
Merge "(bug 70596) fix i18n.twtranslate call"