templates: Add macro for appending the topic to the webhook URL.
templates: Add macro for appending the topic to the webhook URL.

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