Make bar chart tooltip right aligned

Author: tamasapps

lib/src/chart/bar_chart/bar_chart_painter.dart

@@ -394,7 +394,7 @@ class BarChartPainter extends AxisChartPainter<BarChartData> {
  /// draw the background rect with rounded radius
  // ignore: omit_local_variable_types
  Rect rect = Rect.fromLTWH(
- barOffset.dx - (tooltipWidth / 2),
+ barOffset.dx,
  tooltipTop,
  tooltipWidth,
  tooltipHeight,