Generate new pot and po files

Makefile

@@ -68,7 +68,7 @@ serve_bg: stamp-npm
 dist/converse-no-dependencies.js: src webpack.common.js webpack.nodeps.js stamp-npm @converse/headless
 	npm run nodeps
 
-GETTEXT = $(XGETTEXT) --from-code=UTF-8 --language=JavaScript --keyword=__ --keyword=___ --force-po --output=locale/converse.pot --package-name=Converse.js --copyright-holder="Jan-Carel Brand" --package-version=6.0.0 dist/converse-no-dependencies.js -c
+GETTEXT = $(XGETTEXT) --from-code=UTF-8 --language=JavaScript --keyword=__ --keyword=___ --keyword=i18n_ --force-po --output=locale/converse.pot --package-name=Converse.js --copyright-holder="Jan-Carel Brand" --package-version=6.0.0 dist/converse-no-dependencies.js -c
 
 .PHONY: pot
 pot: dist/converse-no-dependencies.js