[lectures/cass_fiscal.md] Need to migrate changes from English to Chinese Versions

[mmcky]

There have been some changes and improvements made to the English Language version of cass_fiscal.md which can be found https://github.com/QuantEcon/lecture-python.myst/blob/main/lectures/cass_fiscal.md

We need to review the latest english language version and migrate changes (translated to Chinese) to this repo.