String isn't extraced from _("...") in py:with attribute

[Jun Omae]

tags/trac-1.0.15/trac/ticket/templates/milestone_view.html@:73#L72​ has _('...') in py:with attribute:

Line
72	<xi:include href="progress_bar_grouped.html" py:if="groups"
73	py:with="summary = _('Shows the milestone completion status grouped by %(grouped_by)s',
74	grouped_by=grouped_by)"/>

However, a string in the gettext keyword is not extracted.

$ git grep -c '%(grouped_by)s' trac-1.0.15 trac/ticket/templates/milestone_view.html
trac-1.0.15:trac/ticket/templates/milestone_view.html:1
$ echo $?
0
$ git grep -c '%(grouped_by)s' trac-1.0.15 trac/locale/*.pot
$ echo $?
1

That string is extracted in Jinja2 template on trunk.