js: make it unnecessary to call babel.format explicitly

[Christian Boos]

On the topic of babel.format, any reason why it couldn't be integrated in gettext?

For example, writing:

title: _("Select ticket %(id)s for modification", {id: tId}),

instead of the cumbersome:

title: babel.format(_("Select ticket %(id)s for modification"), {id: tId}),

The change is fully backward compatible.

Now that Jun started to "customize" our babel.js in r11047… Ok, at some point someone should backport this to Babel:source:trunk/contrib/babel.js ;-)