Improve strategy for opting out of certain font features, e.g. symbolic ligatures

In !107592 (merged) a workaround was added to disable all ligatures, as they were not well received.

It turns out that GitLab Sans (a modified Inter) has some ligatures as well, e.g., for arrows like --> and ---> which aren't desirable.

Unfortunately disabling those means disabling lots of other desirable ligatures/features.

This issue is about finding a better way to achieve the right balance.

Possible fixes

• More nuanced CSS properties
• Modifying GitLab Sans itself
• ???