doc(changelog): record FlightDataExporter extraction, deprecations, and doc updates

Author: CameronBrooks11

CHANGELOG.md

@@ -39,6 +39,9 @@ Attention: The newest changes should be on top -->
 
 ### Changed
 
+- DOC: Update examples to use `FlightDataExporter` and add deprecation notes for legacy `Flight.export_*` methods. (#XXXX)
+- DEP: `Flight.export_data`, `Flight.export_pressures`, `Flight.export_sensor_data`, and `Flight.export_kml` are deprecated. Use `rocketpy.simulation.flight_data_exporter.FlightDataExporter.export_*`. Planned removal in v1.12.0. (#XXXX)
+- MNT: Extract `Flight.export_data`, `export_pressures`, `export_sensor_data`, and `export_kml` into `rocketpy.simulation.flight_data_exporter.FlightDataExporter` (no behavior change). (#XXXX)
 - ENH: _MotorPrints inheritance - issue #460 [#828](https://github.com/RocketPy-Team/RocketPy/pull/828)
 - MNT: fix deprecations and warnings [#829](https://github.com/RocketPy-Team/RocketPy/pull/829)