spelling error correction

Author: chiffa

docs/faq.rst

@@ -66,7 +66,7 @@ Of course, replacing `MOCK_MODULES` with the modules that you want to mock out.
 
         from mock import Mock as MagicMock
 
-If such libraries are installed are installed via ``setup.py``, you also will need to remove all the C-dependent libraries from your ``install_requires`` in the RTD environment.
+If such libraries are installed via ``setup.py``, you also will need to remove all the C-dependent libraries from your ``install_requires`` in the RTD environment.
 
 `Client Error 401` when building documentation
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