refactor: Rename fields for split_by_subscribers().
refactor: Rename fields for split_by_subscribers().

The old name 'subs' was confusing our tooling, since we have
a module called subs.js.

vabs22/zulip,Galexrt/zulip,rishig/zulip,rht/zulip,showell/zulip,ryanbackman/zulip,punchagan/zulip,jphilipsen05/zulip,eeshangarg/zulip,jackrzhang/zulip,jainayush975/zulip,SmartPeople/zulip,Galexrt/zulip,jrowan/zulip,jphilipsen05/zulip,kou/zulip,synicalsyntax/zulip,aakash-cr7/zulip,mahim97/zulip,dhcrzf/zulip,vaidap/zulip,ryanbackman/zulip,rishig/zulip,vaidap/zulip,showell/zulip,rht/zulip,jphilipsen05/zulip,brainwane/zulip,hackerkid/zulip,rishig/zulip,ryanbackman/zulip,Galexrt/zulip,eeshangarg/zulip,verma-varsha/zulip,amanharitsh123/zulip,synicalsyntax/zulip,jrowan/zulip,jackrzhang/zulip,jackrzhang/zulip,punchagan/zulip,brainwane/zulip,dawran6/zulip,hackerkid/zulip,brockwhittaker/zulip,andersk/zulip,brainwane/zulip,JPJPJPOPOP/zulip,rht/zulip,eeshangarg/zulip,susansls/zulip,brockwhittaker/zulip,rht/zulip,aakash-cr7/zulip,jrowan/zulip,SmartPeople/zulip,zulip/zulip,aakash-cr7/zulip,synicalsyntax/zulip,jackrzhang/zulip,synicalsyntax/zulip,dhcrzf/zulip,andersk/zulip,dhcrzf/zulip,punchagan/zulip,jrowan/zulip,showell/zulip,punchagan/zulip,aakash-cr7/zulip,jainayush975/zulip,synicalsyntax/zulip,susansls/zulip,vaidap/zulip,hackerkid/zulip,dawran6/zulip,JPJPJPOPOP/zulip,andersk/zulip,amanharitsh123/zulip,brockwhittaker/zulip,susansls/zulip,zulip/zulip,vabs22/zulip,tommyip/zulip,jainayush975/zulip,timabbott/zulip,vaidap/zulip,andersk/zulip,j831/zulip,kou/zulip,tommyip/zulip,timabbott/zulip,andersk/zulip,mahim97/zulip,zulip/zulip,j831/zulip,jphilipsen05/zulip,dawran6/zulip,eeshangarg/zulip,kou/zulip,kou/zulip,vabs22/zulip,amanharitsh123/zulip,Galexrt/zulip,kou/zulip,rishig/zulip,shubhamdhama/zulip,JPJPJPOPOP/zulip,amanharitsh123/zulip,shubhamdhama/zulip,zulip/zulip,jackrzhang/zulip,vaidap/zulip,shubhamdhama/zulip,tommyip/zulip,eeshangarg/zulip,brockwhittaker/zulip,zulip/zulip,andersk/zulip,synicalsyntax/zulip,showell/zulip,aakash-cr7/zulip,mahim97/zulip,christi3k/zulip,JPJPJPOPOP/zulip,SmartPeople/zulip,showell/zulip,jainayush975/zulip,Galexrt/zulip,tommyip/zulip,rht/zulip,SmartPeople/zulip,vabs22/zulip,verma-varsha/zulip,zulip/zulip,shubhamdhama/zulip,verma-varsha/zulip,brainwane/zulip,mahim97/zulip,jainayush975/zulip,jphilipsen05/zulip,susansls/zulip,jrowan/zulip,ryanbackman/zulip,brockwhittaker/zulip,punchagan/zulip,shubhamdhama/zulip,christi3k/zulip,aakash-cr7/zulip,dawran6/zulip,christi3k/zulip,susansls/zulip,rishig/zulip,synicalsyntax/zulip,ryanbackman/zulip,mahim97/zulip,dawran6/zulip,mahim97/zulip,kou/zulip,hackerkid/zulip,JPJPJPOPOP/zulip,susansls/zulip,kou/zulip,andersk/zulip,jackrzhang/zulip,tommyip/zulip,hackerkid/zulip,jrowan/zulip,amanharitsh123/zulip,dhcrzf/zulip,christi3k/zulip,timabbott/zulip,jainayush975/zulip,SmartPeople/zulip,showell/zulip,timabbott/zulip,rht/zulip,j831/zulip,rishig/zulip,eeshangarg/zulip,Galexrt/zulip,dhcrzf/zulip,brockwhittaker/zulip,JPJPJPOPOP/zulip,amanharitsh123/zulip,punchagan/zulip,shubhamdhama/zulip,rht/zulip,verma-varsha/zulip,jackrzhang/zulip,SmartPeople/zulip,dawran6/zulip,timabbott/zulip,eeshangarg/zulip,brainwane/zulip,zulip/zulip,rishig/zulip,j831/zulip,christi3k/zulip,j831/zulip,tommyip/zulip,jphilipsen05/zulip,Galexrt/zulip,ryanbackman/zulip,brainwane/zulip,shubhamdhama/zulip,vabs22/zulip,tommyip/zulip,j831/zulip,dhcrzf/zulip,vaidap/zulip,verma-varsha/zulip,christi3k/zulip,vabs22/zulip,brainwane/zulip,hackerkid/zulip,timabbott/zulip,hackerkid/zulip,dhcrzf/zulip,punchagan/zulip,showell/zulip,verma-varsha/zulip,timabbott/zulip