Remove unused rounding modes Trunc and Expand

[barakman]

Fixes #5411

In the Rounding-Modes API (in the Math library):

    enum Rounding {
        Floor, // Toward negative infinity
        Ceil, // Toward positive infinity
        Trunc, // Toward zero
        Expand // Away from zero
    }

Remove the last two options, which are not in use throughout the codebase.

PR Checklist

• Tests
• Documentation
• Changeset entry (run npx changeset add)

[changeset-bot]

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[barakman]

⚠️ No Changeset found

Latest commit: 6a441be

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets
Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

This PR introduces an API-breaking change, so in theory, the changeset should include a major-version update.
On the other hand, the changed part in the API is not used anywhere in the current version, so it is possible that a minor-version update or even a patch-version update will suffice.

[Amxx]

Hello @barakman

Rounding mode Trunc and Expand have been introduced from the start so that we couldn't unambiguously expand the library to signed integers in the future. While this is not (yet) available in our library, there may be code that depends on our library to define these operation.

Removing enum entries is a breaking change, and we don't allow such modification without a very strong reason.

[barakman]

Removing enum entries is a breaking change, and we don't allow such modification without a very strong reason.

The reasons are explained in the associated issue (#5411), as by changing this API to support only unsigned input, it becomes easier (and cleaner) to:

1. Support an additional rounding mode, namely, round-to-nearest
2. Get rid of the enum altogether, thus reducing the gas consumption of all related functions

Whether these are strong reasons is subjected to opinion, which I will leave for your dev team to decide.

One way to handle the API-break issue, is by implementing the new functions ("funcFloor" and "funcCeil" per each "func") independently and without removing the current API (which could later be deprecated if chosen to).

[Amxx]

Lets discuss all that in the issue before doing any breaking implementation.