Issue 933 reference isort settings (#936)

* Fixed link to `isort.toml` in config docs

The link was supposed to point to `isort.toml`, but did actually point
to `flake8.toml`. This is fixed now.

* Updated docstring to reference `isort` settings

`isort` settings need to include `multi_line_output = 3` option to not
collide with WSP318. The docstring has been updated with a reference.

* Updated CHANGELOG

* Fixed which docstring is update

I messed up before and changed the docstring of WSP317 instead of 318.
This is fixed now.

CHANGELOG.md

@@ -46,6 +46,7 @@ We used to have incremental versioning before `0.1.0`.
 - Replace `scripts/tokens.py` with an external tool
 - Improves violation code testing
 - Improves testing of `.. versionchanged` and `previous_codes` properties
+- Reference `isort` settings requirement for compliance with WSP318 in docstring
 
 
 ## 0.12.5

docs/pages/usage/configuration.rst

@@ -40,7 +40,7 @@ file is available with the core settings for ``flake8``.
 We also use ``flake8-isort`` to style our imports.
 You will need to update your configuration with the following lines:
 Otherwise, your ``isort`` will complain about your imports.
-Our `isort.toml <https://github.com/wemake-services/wemake-python-styleguide/blob/master/styles/flake8.toml>`_
+Our `isort.toml <https://github.com/wemake-services/wemake-python-styleguide/blob/master/styles/isort.toml>`_
 file is available with the core settings for ``isort``.
 
 All recommended settings can be found in our `styleguide.toml <https://github.com/wemake-services/wemake-python-styleguide/blob/master/styles/styleguide.toml>`_.

wemake_python_styleguide/violations/consistency.py

@@ -783,6 +783,14 @@ def test():
         def test():
                     print('test')
 
+    This rule is consistent with the "Vertical Hanging Indent" option for
+    ``multi_line_output`` setting of ``isort``. To avoid conflicting rules,
+    you should set ``multi_line_output = 3`` in the ``isort`` settings.
+
+    See also:
+        https://github.com/timothycrosley/isort#multi-line-output-modes
+        https://github.com/wemake-services/wemake-python-styleguide/blob/master/styles/isort.toml
+
     .. versionadded:: 0.6.0
 
     """