The following two source files use the same target: [numba.rst](https://raw.githubusercontent.com/QuantEcon/lecture-python-programming/master/source/rst/numba.rst) & [need_for_speed.rst](https://raw.githubusercontent.com/QuantEcon/lecture-python-programming/master/source/rst/need_for_speed.rst). If this not intended, would be happy to update the target in `numba.rst` to `numba`.