Remove docs on Python 2.7 and 3.4 Support (#9957)

This extensive explanation is not need anymore because they are now
unsupported for a long time.

Instead add as short section on Python version compatibility in the
backward compatibility docs.

Author: timhoffm

doc/en/backwards-compatibility.rst

@@ -77,3 +77,18 @@ Deprecation Roadmap
 Features currently deprecated and removed in previous releases can be found in :ref:`deprecations`.
 
 We track future deprecation and removal of features using milestones and the `deprecation <https://github.com/pytest-dev/pytest/issues?q=label%3A%22type%3A+deprecation%22>`_ and `removal <https://github.com/pytest-dev/pytest/labels/type%3A%20removal>`_ labels on GitHub.
+
+
+Python version support
+======================
+
+Released pytest versions support all Python versions that are actively maintained at the time of the release:
+
+==============  ===================
+pytest version  min. Python version
+==============  ===================
+7.1+            3.7+
+6.2 - 7.0       3.6+
+5.0 - 6.1       3.5+
+3.3 - 4.6       2.7, 3.4+
+==============  ===================

doc/en/changelog.rst

@@ -2618,7 +2618,8 @@ Important
 
 This release is a Python3.5+ only release.
 
-For more details, see our :std:doc:`Python 2.7 and 3.4 support plan <py27-py34-deprecation>`.
+For more details, see our `Python 2.7 and 3.4 support plan
+<https://docs.pytest.org/en/7.0.x/py27-py34-deprecation.html>`_.
 
 Removals
 --------
@@ -2842,7 +2843,11 @@ Features
 
 - :issue:`6870`: New ``Config.invocation_args`` attribute containing the unchanged arguments passed to ``pytest.main()``.
 
-  Remark: while this is technically a new feature and according to our :ref:`policy <what goes into 4.6.x releases>` it should not have been backported, we have opened an exception in this particular case because it fixes a serious interaction with ``pytest-xdist``, so it can also be considered a bugfix.
+  Remark: while this is technically a new feature and according to our
+  `policy <https://docs.pytest.org/en/7.0.x/py27-py34-deprecation.html#what-goes-into-4-6-x-releases>`_
+  it should not have been backported, we have opened an exception in this
+  particular case because it fixes a serious interaction with ``pytest-xdist``,
+  so it can also be considered a bugfix.
 
 Trivial/Internal Changes
 ------------------------
@@ -3014,7 +3019,8 @@ Important
 
 The ``4.6.X`` series will be the last series to support **Python 2 and Python 3.4**.
 
-For more details, see our :std:doc:`Python 2.7 and 3.4 support plan <py27-py34-deprecation>`.
+For more details, see our `Python 2.7 and 3.4 support plan
+<https://docs.pytest.org/en/7.0.x/py27-py34-deprecation.html>`_.
 
 
 Features

doc/en/contents.rst

@@ -85,7 +85,6 @@ Further topics
 
    backwards-compatibility
    deprecations
-   py27-py34-deprecation
 
    contributing
    development_guide