overflow property
How to handle data labels that flow outside the plot area. The
default is "justify", which aligns them inside the plot area.
For columns and bars, this means it will be moved inside the bar.
To display data labels outside the plot area, set crop to
false and overflow to "allow".
API Docs: https://api.highcharts.com/highcharts/series.sankey.dataLabels.overflow
Implementation
String? overflow;