Function removeLine

removeLine(chart: RpeJson, lineIndex: number): RpeJson
Remove a line from the chart by index.

All father references in sibling lines are updated:
- References to the removed line are reset to -1 (no parent).
- References to lines after the removed line are decremented by 1.
Parameters
- chart: RpeJson
  The RPE chart (modified in place).
- lineIndex: number
  Index of the line to remove.
Returns RpeJson
The chart (for chaining).
Example
```
removeLine(chart, 2); // removes line at index 2
```
- Defined in chart-utils.ts:372