Fix minor format spec breaking of rustfmt

[termoshtt]

Fix https://github.com/rust-ndarray/ndarray-linalg/runs/2101143616

[codecov]

Codecov Report

Merging #269 (a22c836) into master (7925aa6) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #269      +/-   ##
==========================================
+ Coverage   89.02%   89.04%   +0.01%     
==========================================
  Files          71       71              
  Lines        3582     3586       +4     
==========================================
+ Hits         3189     3193       +4     
  Misses        393      393              

Impacted Files	Coverage Δ
ndarray-linalg/src/solve.rs	72.65% <100.00%> (+0.43%)	⬆️
ndarray-linalg/src/solveh.rs	73.26% <100.00%> (+0.54%)	⬆️

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