i18n: Recognize a little more Handlebars syntax in makemessages.
i18n: Recognize a little more Handlebars syntax in makemessages.

Usually we write translation expressions as `{{t ... }}`, but `{{ t ... }}`
is equally valid as far as Handlebars is concerned, and it matches how we
usually write simple variable substitutions, as `{{ ... }}`.  So occasionally
someone writes `{{ t ... }}`; currently there are two examples of this
in the codebase, in `settings/bot-{settings,list-admin}.handlebars`.

Probably it'd be good to pick a style and enforce it uniformly, but
until we do, the other style shouldn't break translation.

showell/zulip,Galexrt/zulip,Galexrt/zulip,timabbott/zulip,timabbott/zulip,verma-varsha/zulip,showell/zulip,hackerkid/zulip,eeshangarg/zulip,brainwane/zulip,zulip/zulip,jackrzhang/zulip,brockwhittaker/zulip,tommyip/zulip,showell/zulip,verma-varsha/zulip,punchagan/zulip,eeshangarg/zulip,rishig/zulip,shubhamdhama/zulip,vabs22/zulip,Galexrt/zulip,Galexrt/zulip,eeshangarg/zulip,rht/zulip,dhcrzf/zulip,synicalsyntax/zulip,jrowan/zulip,showell/zulip,rishig/zulip,vaidap/zulip,dhcrzf/zulip,rishig/zulip,brainwane/zulip,tommyip/zulip,brockwhittaker/zulip,jackrzhang/zulip,brockwhittaker/zulip,hackerkid/zulip,rht/zulip,vabs22/zulip,timabbott/zulip,shubhamdhama/zulip,jackrzhang/zulip,eeshangarg/zulip,eeshangarg/zulip,synicalsyntax/zulip,amanharitsh123/zulip,amanharitsh123/zulip,synicalsyntax/zulip,zulip/zulip,synicalsyntax/zulip,rishig/zulip,jackrzhang/zulip,vaidap/zulip,dhcrzf/zulip,kou/zulip,brainwane/zulip,zulip/zulip,jackrzhang/zulip,vabs22/zulip,tommyip/zulip,mahim97/zulip,vabs22/zulip,punchagan/zulip,vaidap/zulip,eeshangarg/zulip,rishig/zulip,shubhamdhama/zulip,mahim97/zulip,andersk/zulip,vaidap/zulip,vaidap/zulip,synicalsyntax/zulip,brainwane/zulip,hackerkid/zulip,zulip/zulip,punchagan/zulip,showell/zulip,Galexrt/zulip,timabbott/zulip,vabs22/zulip,synicalsyntax/zulip,rht/zulip,jrowan/zulip,brockwhittaker/zulip,kou/zulip,jrowan/zulip,amanharitsh123/zulip,verma-varsha/zulip,tommyip/zulip,brainwane/zulip,rishig/zulip,Galexrt/zulip,dhcrzf/zulip,tommyip/zulip,brainwane/zulip,jackrzhang/zulip,verma-varsha/zulip,verma-varsha/zulip,dhcrzf/zulip,shubhamdhama/zulip,rht/zulip,rht/zulip,amanharitsh123/zulip,andersk/zulip,mahim97/zulip,andersk/zulip,tommyip/zulip,timabbott/zulip,zulip/zulip,zulip/zulip,hackerkid/zulip,mahim97/zulip,synicalsyntax/zulip,kou/zulip,rishig/zulip,rht/zulip,Galexrt/zulip,eeshangarg/zulip,timabbott/zulip,kou/zulip,andersk/zulip,andersk/zulip,hackerkid/zulip,rht/zulip,jrowan/zulip,jrowan/zulip,jrowan/zulip,zulip/zulip,punchagan/zulip,kou/zulip,brockwhittaker/zulip,mahim97/zulip,tommyip/zulip,amanharitsh123/zulip,punchagan/zulip,dhcrzf/zulip,kou/zulip,timabbott/zulip,brockwhittaker/zulip,kou/zulip,vabs22/zulip,hackerkid/zulip,jackrzhang/zulip,amanharitsh123/zulip,verma-varsha/zulip,dhcrzf/zulip,hackerkid/zulip,showell/zulip,shubhamdhama/zulip,punchagan/zulip,andersk/zulip,vaidap/zulip,brainwane/zulip,mahim97/zulip,shubhamdhama/zulip,punchagan/zulip,showell/zulip,andersk/zulip,shubhamdhama/zulip