[BUG] Fix incorrect handling of negative n in BaseDistribution.head()

[mohityadav8]

Reference Issues/PRs

Fixes #894

What does this implement/fix? Explain your changes.

This PR fixes incorrect handling of negative values of n in BaseDistribution.head().

The current implementation uses:

n = N - n

When n is negative, this produces incorrect results.

Example:
If N = 10 and n = -2, the current logic computes:

n = 10 - (-2) = 12

This value is then clipped to 10 and returns all rows instead of returning
all rows except the last two.

The documented behavior states:
"For negative n, returns all rows except the last n."

This PR updates the logic to:

n = N + n

which correctly computes the intended number of rows.

Does your contribution introduce a new dependency? If yes, which one?

No new dependencies were introduced.

What should a reviewer concentrate their feedback on?

• Correctness of the updated logic in BaseDistribution.head()
• Whether the behavior matches the documented behavior for negative n

Did you add any tests for the change?

No new tests were added. Existing tests pass successfully.

Any other comments?

All existing tests pass locally after this change.

PR checklist

• Code builds successfully
• Tests pass locally
• No new dependencies added

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[mohityadav8]

Previously worked on in #895

[mohityadav8]

Hi @felipeangelimvieira and @fkiraly
It looks like the workflows are awaiting maintainer approval and the PR also requires a code owner review.
Could you please approve the workflows and review the PR when convenient?
Thanks!

[fkiraly]

I think you haven't actually tried to run the code because it does not run if you try.

Is this AI generated copy-paste?

[fkiraly]

I fixed it

[mohityadav8]

Thanks☺️ @fkiraly