Fix broken link

Author: untitaker

docs/installation.rst

@@ -44,7 +44,7 @@ following things are installed:
 - Python 3.5+ and pip.
 - ``libxml`` and ``libxslt``
 - ``zlib``
-- Linux or OS X. **Windows is not supported, see :gh:`535`.**
+- Linux or OS X. **Windows is not supported**, see :gh:`535`.
 
 On Linux systems, using the distro's package manager is the best
 way to do this, for example, using Ubuntu::