Dear @mmcky , I find some internal references in the ``MYST`` are broken. For example, in lecture [optgrowth_fast](https://quantecon.github.io/lecture-python.myst/optgrowth_fast.html#id2) (left: ``MYST``. right: ``RST``),  in lecture [34_ifp](https://quantecon.github.io/lecture-python.myst/ifp.html),  The same issue exists in the following lectures (keep updating): - [31_optgrowth_fast](https://quantecon.github.io/lecture-python.myst/optgrowth_fast.html#id2) - [34_ifp](https://quantecon.github.io/lecture-python.myst/ifp.html)