Improve verbose diff output with sequences.

Before:

.. code-block::

    E   AssertionError: assert ['version', '...version_info'] == ['version', '...version', ...]
    E     Right contains 3 more items, first extra item: ' '
    E     Full diff:
    E     - ['version', 'version_info', 'sys.version', 'sys.version_info']
    E     + ['version',
    E     +  'version_info',
    E     +  'sys.version',
    E     +  'sys.version_info',
    E     +  ' ',
    E     +  'sys.version',
    E     +  'sys.version_info']

After:

.. code-block::

    E   AssertionError: assert ['version', '...version_info'] == ['version', '...version', ...]
    E     Right contains 3 more items, first extra item: ' '
    E     Full diff:
    E       [
    E        'version',
    E        'version_info',
    E        'sys.version',
    E        'sys.version_info',
    E     +  ' ',
    E     +  'sys.version',
    E     +  'sys.version_info',
    E       ]