unminify: Clean up unnecessary repetition of webpack:/// URLs.
unminify: Clean up unnecessary repetition of webpack:/// URLs.

This takes stacktrace lines that used to look like this:

n@https://chat.zulip.org/static/webpack-bundles/app.2385793af60f0b082ee9.js:1:12680
       = webpack:///./static/js/blueslip.js line 241 column 1
dispatch@https://chat.zulip.org/static/webpack-bundles/app.2385793af60f0b082ee9.js:52:37878
       = webpack:////srv/zulip-npm-cache/8ea4cd291dd23441aec0f298b77b6ddc0d0a7a56/node_modules/jquery/dist/jquery.js line 5182 column 1

to have the even-numbered lines look like this:
       = ./static/js/blueslip.js line 241 column 1
dispatch@https://chat.zulip.org/static/webpack-bundles/app.2385793af60f0b082ee9.js:52:37878
       = /srv/zulip-npm-cache/8ea4cd291dd23441aec0f298b77b6ddc0d0a7a56/node_modules/jquery/dist/jquery.js line 5182 column 1

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