Fix ordinal() suffix for negative integers

[fbindakheel]

Bug

ordinal() returns the wrong suffix for negative integers:

>>> humanize.ordinal(-1)
'-1th' # expected '-1st'
>>> humanize.ordinal(-2)
'-2th' # expected '-2nd'
>>> humanize.ordinal(-21)
'-21th' # expected '-21st'

The docstring states the function "works for any integer," so negatives are in scope.

Root cause

The suffix is selected with value % 10 / value % 100. Python's modulo on negative numbers returns a non-negative result (-1 % 10 == 9), so negative values index into the wrong _ORDINAL_SUFFIXES slot (9 → "th"). Some negatives (e.g. -11, -12) happen to land on "th" correctly by coincidence, but -1, -2, -3, -21, -101, etc. are wrong.

Fix

Compute the suffix from abs(value). The displayed number keeps its sign. One-line logic change.

Tests

Added negative cases to the test_ordinal parametrization (-1→-1st, -2→-2nd, -3→-3rd, -11→-11th, -21→-21st, -101→-101st, -111→-111th, etc.). Verified the new cases fail on the current code and pass with the fix; full suite (696 tests) passes.

[codspeed-hq]

Merging this PR will not alter performance

✅ 15 untouched benchmarks

---

_{Comparing fbindakheel:fix/ordinal-negative-suffix (3af1a68) with main (0a06a3d)}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.55%. Comparing base (0a06a3d) to head (3af1a68).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #321 +/- ##
=======================================
Coverage 99.55% 99.55% =======================================
Files 12 12 Lines 900 901 +1 =======================================
+ Hits 896 897 +1 
Misses 4 4 

Flag	Coverage Δ
macos-latest	97.55% <100.00%> (+<0.01%)	⬆️
ubuntu-latest	97.55% <100.00%> (+<0.01%)	⬆️
windows-latest	95.67% <100.00%> (+<0.01%)	⬆️

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[hugovk]

The docstring states the function "works for any integer," so negatives are in scope.

Strictly speaking maybe, but perhaps the original intent was for "any positive integer"?

Stepping back a moment: do negative ordinals like -1st, -2nd or -21st even make sense?