Improve documentation for common sequence methods

My suggestion for stdtypes.rst:

Leave the statements and operators in the tables, but document all methods using normal Sphinx syntax, e.g.:

.. method:: sequence.append(value, /)

Then make anchors for list.append(), bytearray.append(), deque.append(), etc linked to this definition (there is a way to do this without cluttering the text and index). For example:

.. method:: list.append(value, /)
            bytearray.append(value, /)
   :no-typesetting:
   :no-index-entry:
.. method:: sequence.append(value, /)