Note when to backport changes (#1169)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>

developer-workflow/development-cycle.rst

@@ -77,11 +77,17 @@ releases; the terms are used interchangeably. These releases have a
 **micro version** number greater than zero.
 
 The only changes allowed to occur in a maintenance branch without debate are
-bug fixes.  Also, a general rule for maintenance branches is that compatibility
+bug fixes, test improvements, and edits to the documentation.
+Also, a general rule for maintenance branches is that compatibility
 must not be broken at any point between sibling micro releases (3.5.1, 3.5.2,
 etc.).  For both rules, only rare exceptions are accepted and **must** be
 discussed first.
 
+Backporting changes reduces the risk of future conflicts.
+For documentation, it increases the visibility of improvements,
+since most readers access the `stable documentation <https://docs.python.org/3/>`__
+rather than the `development documentation <https://docs.python.org/dev/>`__.
+
 A new maintenance branch is normally created when the next feature release
 cycle reaches feature freeze, i.e. at its first beta pre-release.
 From that point on, changes intended for remaining pre-releases, the final

versions.rst

@@ -50,7 +50,7 @@ Status key
     but new source-only versions can be released
 :end-of-life: release cycle is frozen; no further changes can be pushed to it.
 
-See also the :ref:`devcycle` page for more information about branches.
+See also the :ref:`devcycle` page for more information about branches and backporting.
 
 By default, the end-of-life is scheduled 5 years after the first release,
 but can be adjusted by the release manager of each branch.  All Python 2