some manual python2 metadata cleanup

docs/source/user/error-codes.rst

@@ -100,8 +100,6 @@ generates its own :term:`error code`\ s for ``pyflakes``:
 +------+---------------------------------------------------------------------+
 | F811 | redefinition of unused ``name`` from line ``N``                     |
 +------+---------------------------------------------------------------------+
-| F812 | list comprehension redefines ``name`` from line ``N``               |
-+------+---------------------------------------------------------------------+
 | F821 | undefined name ``name``                                             |
 +------+---------------------------------------------------------------------+
 | F822 | undefined name ``name`` in ``__all__``                              |
@@ -116,9 +114,6 @@ generates its own :term:`error code`\ s for ``pyflakes``:
 | F901 | ``raise NotImplemented`` should be ``raise NotImplementedError``    |
 +------+---------------------------------------------------------------------+
 
-Note that some of these entries behave differently on Python 2 and Python 3,
-for example F812 is specific to Python 2 only.
-
 We also report one extra error: ``E999``. We report ``E999`` when we fail to
 compile a file into an Abstract Syntax Tree for the plugins that require it.
 

docs/source/user/invocation.rst

@@ -14,25 +14,25 @@ like so:
 
 Where you simply allow the shell running in your terminal to locate |Flake8|.
 In some cases, though, you may have installed |Flake8| for multiple versions
-of Python (e.g., Python 2.7 and Python 3.5) and you need to call a specific
+of Python (e.g., Python 3.8 and Python 3.9) and you need to call a specific
 version. In that case, you will have much better results using:
 
 .. prompt:: bash
 
-    python2.7 -m flake8
+    python3.8 -m flake8
 
 Or
 
 .. prompt:: bash
 
-    python3.5 -m flake8
+    python3.9 -m flake8
 
 Since that will tell the correct version of Python to run |Flake8|.
 
 .. note::
 
-    Installing |Flake8| once will not install it on both Python 2.7 and
-    Python 3.5. It will only install it for the version of Python that
+    Installing |Flake8| once will not install it on both Python 3.8 and
+    Python 3.9. It will only install it for the version of Python that
     is running pip.
 
 It is also possible to specify command-line options directly to |Flake8|:

docs/source/user/using-plugins.rst

@@ -24,10 +24,8 @@ appropriate of:
     pip install <plugin-name>
     pip3 install <plugin-name>
     python -m pip install <plugin-name>
-    python2.7 -m pip install <plugin-name>
     python3 -m pip install <plugin-name>
-    python3.4 -m pip install <plugin-name>
-    python3.5 -m pip install <plugin-name>
+    python3.9 -m pip install <plugin-name>
 
 To install the plugin, where ``<plugin-name>`` is the package name on PyPI_.
 To verify installation use: