Fix typos and run codespell in CI

[saraedum]

Checklist

• [x] Added an entry in doc/news/.
• [x] Added a test/benchmark for this change. No, does not apply.

TODO

• [x] Remove the libcxx pin.

[codecov[bot]]

Codecov Report

Merging #259 (21b3ae7) into master (af0277e) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #259   +/-   ##
=======================================
  Coverage   92.15%   92.15%           
=======================================
  Files         105      105           
  Lines        2117     2117           
=======================================
  Hits         1951     1951           
  Misses        166      166           

Impacted Files	Coverage Δ
libeantic/src/fmpq_poly_extra/set_str_pretty.c	92.55% <ø> (ø)
libeantic/src/renf_elem/fdiv.c	71.79% <ø> (ø)

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[saraedum]

The CI errors seem to be due to a recent libcxx update that breaks macOS here: https://github.com/conda-forge/libcxx-feedstock/issues/111

[saraedum]

We still need to wait for https://github.com/conda-forge/conda-forge-repodata-patches-feedstock/pull/414 for this to work.