message: TimeRangeChangeEventHandler type added
diff: @@ -45,13 +45,20 @@ function handleCrosshairMoved(param) {
  console.log(`A user moved the crosshair to (${param.point.x}, ${param.point.y}) point, the time is ${param.time}`);
  }
  -chart.subscribeCrosshairMove(handleClick);
  +chart.subscribeCrosshairMove(handleCrosshairMoved);
  // ... after some time
  -chart.unsubscribeCrosshairMove(handleClick);
  +chart.unsubscribeCrosshairMove(handleCrosshairMoved);
  ```
  +## Time range change
  +
  +|Name|Description|
  +|-|-|
  +|`subscribeVisibleTimeRangeChange(handler: TimeRangeChangeEventHandler): void;`|Adds a subscription to visible range changes to receive notification about visible range of data changes|
  +|`unsubscribeVisibleTimeRangeChange(handler: TimeRangeChangeEventHandler): void;`|Removes a subscription to visible range changes|
  +
  ## Types
  ### MouseEventHandler
  @@ -78,9 +85,10 @@ export type MouseEventHandler = (param: MouseEventParams) => void;
  TimeRangeChangeEventHandler is a type of callback that is being used to get notified about chart time range changes.
  -|Name|Description|
  -|-|-|
  -|`subscribeVisibleTimeRangeChange(handler: TimeRangeChangeEventHandler): void;`|Adds a subscription to visible range changes to receive notification about visible range of data changes|
  -|`unsubscribeVisibleTimeRangeChange(handler: TimeRangeChangeEventHandler): void;`|Removes a subscription to visible range changes|
  +```typescript
  +export type TimeRangeChangeEventHandler = (timeRange: TimeRange | null) => void;
  +```
  +`TimeRange` is an object with two `time` fields - data of the first and the last time points of the current timerange.
  +`null` is returned if the chart has no data at all.
  