Apply ruff preview rule RUF046

[DimitriPapadopoulos]

RUF046 Value being casted is already an integer

TODO:

• Unit tests and/or doctests in docstrings
• Tests pass locally
• Docstrings and API docs for any new/modified user-facing classes and functions
• Changes documented in docs/release.rst
• Docs build locally
• GitHub Actions CI passes
• Test coverage to 100% (Codecov passes)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.81%. Comparing base (5502dc8) to head (d718988).
Report is 9 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #687   +/-   ##
=======================================
  Coverage   99.81%   99.81%           
=======================================
  Files          62       62           
  Lines        2752     2752           
=======================================
  Hits         2747     2747           
  Misses          5        5           

Files with missing lines	Coverage Δ
numcodecs/quantize.py	100.00% <100.00%> (ø)