streams: Add hotkey for content-editable enter.
streams: Add hotkey for content-editable enter.

When you enter, it should click the checkmark, which would save the
current input of the input section.

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