Fix typos in CONTRIBUTING.rst

Author: gnikonorov

CONTRIBUTING.rst

@@ -30,12 +30,11 @@ Preparing Pull Requests
 #. Install `tox <https://tox.readthedocs.io/en/latest/>`_::
 
    Tox is used to run all the tests and will automatically setup virtualenvs
-   to run the tests in.
-   (will implicitly use http://www.virtualenv.org/en/latest/)::
+   to run the tests in. Implicitly http://www.virtualenv.org/en/latest/ is used::
 
     $ pip install tox
     $ tox -e linting,py37
 
 #. Follow **PEP-8** for naming and `black <https://github.com/psf/black>`_ for formatting.
 
-#. Add a line item to the current **unreleased** verrsion in ``CHANGES.rst``, unless the change is trivial.
+#. Add a line item to the current **unreleased** version in ``CHANGES.rst``, unless the change is trivial.