[Bug]: Abuse of OTF discretionary ligatures

[skylee03]

This is actually a issue with Sassline:

• Disable discretionary ligatures of OTF jakegiltsoff/sassline#62

However, since it is no longer actively maintained, I think we can just fix it in Alembic.

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Sometimes, if a word happens to have a substring that is a mathematical unit, it will be displayed in a weird way.

• Weird text format in DG nus-cs2113-AY2324S1/pe-dev-response#455