Merge pull request #24112 from meeseeksmachine/auto-backport-of-pr-24…

…109-on-v3.6.x

Backport PR #24109 on branch v3.6.x (DOC: add API change note for colorbar deprecation)

doc/api/next_api_changes/deprecations/24088-JMK.rst

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+Colorbars for orphaned mappables are deprecated, but no longer raise
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Before 3.6.0, Colorbars for mappables that do not have a parent axes would
+steal space from the current Axes.  3.6.0 raised an error on this, but without
+a deprecation cycle.  For 3.6.1 this is reverted, the current axes is used,
+but a deprecation warning is shown instead.  In this undetermined case users
+and libraries should explicitly specify what axes they want space to be stolen
+from: ``fig.colorbar(mappable, ax=plt.gca())``.