[inequality] Translation Update (#129)

* [inequality] Translation Update

* Rename inequality.md to lectures/ inequality.md

* fix file name

* updates

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Co-authored-by: Humphrey Yang <39026988+HumphreyYang@users.noreply.github.com>
Co-authored-by: Humphrey Yang <u6474961@anu.edu.au>

Author: XYshi725