Update 2.9.0 release notes following recent bug fixes

Author: PierreRaybaut

doc/release_notes/release_2.09.md

@@ -29,6 +29,26 @@
     visual state into the matching parameter set, instead of overwriting the base
     (normal) style with the selected style
   * This preserves distinct normal and selected appearance for markers
+* Fixed error-bar curve cursor snapping: clicking near an error-bar bound on an
+  `ErrorBarCurveItem` now correctly returns the closest bar end coordinate.
+  Previously a typo (`abs(y - y)` / `abs(x - x)` instead of `abs(y - yi)` /
+  `abs(x - xi)`) made the snap-to-bound branches dead code, so the closest
+  coordinate was always the central curve point regardless of cursor position
+* Fixed image export via `Figure.print_` (`plotpy.pyplot`) leaking the underlying
+  `QPainter`: the painter is now always released, even when an axis fails to
+  render. This avoids "QPainter::begin: A paint device can only be painted by
+  one painter at a time" warnings, GDI/GL resource leaks, and truncated output
+  files on subsequent paints
+* Fixed `vector_projection` raising a division-by-zero warning and returning NaN
+  coordinates when the two reference points A and B coincided. The function now
+  detects the degenerate zero-length AB vector and returns point B
+* Fixed `scale_data_to_dtype` (`plotpy.io`) producing NaN values when the input
+  array was constant (`dmax == dmin`). The function now returns a finite
+  constant array set to the target dtype's minimum value instead of dividing by
+  zero
+* Fixed `get_nan_min` / `get_nan_max` (`plotpy.mathutils.arrayfuncs`) raising
+  `ValueError` on empty arrays and emitting `RuntimeWarning` on all-NaN inputs.
+  Both helpers now return NaN for empty or fully-NaN arrays without warnings
 
 🔧 Other changes: