Corrected typo in installation troubleshooting section

Author: Andrew Hearin

docs/installation_troubleshooting.rst

@@ -14,12 +14,12 @@ the development team and raise an Issue on
 
 1. Older versions of the gcc compiler may not support all the optimization
 flags that are used to compile the Cython code. These flags are chosen according
-to the ``extra_compiler_args`` list of strings that appears in the handful of
+to the ``extra_compile_args`` list of strings that appears in the handful of
 ``setup_package.py`` files throughout the code. If this list contains a flag
 not used by your version of gcc, you can simply delete each
 appearance of the offending flag, and then install the code by
 building the modified source code.
-See `GitHub Issue 561 <https://github.com/astropy/halotools/issues/561>`_
+See `GitHub Issue 561 <https://github.com/astropy/halotools/issues/561>`_ for further details.
 
 2. If you are a Mac user and you are not using the version of gcc that ships
 with OS X, you may need to temporarily switch compilers to clang.