browser-support: Add codepointat polyfill to `common` entry point.
browser-support: Add codepointat polyfill to `common` entry point.

Adds string.prototype.codepointat which was added as a polyfill
earlier to the project but was not added to `common` entry point.

rishig/zulip,eeshangarg/zulip,rht/zulip,zulip/zulip,andersk/zulip,brainwane/zulip,synicalsyntax/zulip,synicalsyntax/zulip,punchagan/zulip,jackrzhang/zulip,kou/zulip,eeshangarg/zulip,hackerkid/zulip,rht/zulip,punchagan/zulip,synicalsyntax/zulip,kou/zulip,zulip/zulip,kou/zulip,synicalsyntax/zulip,tommyip/zulip,showell/zulip,showell/zulip,timabbott/zulip,brainwane/zulip,jackrzhang/zulip,jackrzhang/zulip,tommyip/zulip,eeshangarg/zulip,shubhamdhama/zulip,brainwane/zulip,andersk/zulip,hackerkid/zulip,eeshangarg/zulip,timabbott/zulip,eeshangarg/zulip,dhcrzf/zulip,tommyip/zulip,hackerkid/zulip,rht/zulip,rht/zulip,timabbott/zulip,shubhamdhama/zulip,andersk/zulip,punchagan/zulip,shubhamdhama/zulip,andersk/zulip,rishig/zulip,rht/zulip,showell/zulip,timabbott/zulip,rishig/zulip,zulip/zulip,shubhamdhama/zulip,zulip/zulip,dhcrzf/zulip,rht/zulip,kou/zulip,shubhamdhama/zulip,zulip/zulip,kou/zulip,brainwane/zulip,showell/zulip,zulip/zulip,hackerkid/zulip,jackrzhang/zulip,hackerkid/zulip,dhcrzf/zulip,shubhamdhama/zulip,dhcrzf/zulip,jackrzhang/zulip,punchagan/zulip,dhcrzf/zulip,timabbott/zulip,rishig/zulip,eeshangarg/zulip,brainwane/zulip,showell/zulip,jackrzhang/zulip,rht/zulip,dhcrzf/zulip,dhcrzf/zulip,showell/zulip,andersk/zulip,showell/zulip,brainwane/zulip,punchagan/zulip,tommyip/zulip,jackrzhang/zulip,andersk/zulip,tommyip/zulip,rishig/zulip,kou/zulip,eeshangarg/zulip,hackerkid/zulip,synicalsyntax/zulip,kou/zulip,brainwane/zulip,rishig/zulip,timabbott/zulip,timabbott/zulip,shubhamdhama/zulip,synicalsyntax/zulip,punchagan/zulip,synicalsyntax/zulip,hackerkid/zulip,tommyip/zulip,tommyip/zulip,zulip/zulip,andersk/zulip,rishig/zulip,punchagan/zulip