revert change to `highcharts.js` in fcd3e9ad1afd76493ec44a7d710513fe1e8fff9e
revert change to `highcharts.js` in fcd3e9ad1afd76493ec44a7d710513fe1e8fff9e

This change corrupted the default `pointFormat`.

KenanY/highcharts-browserify,soldair/highcharts-browserify