Relax type bounds for LeastSquaresSvd family

[janmarthedal]

Allow for the linear operator and right-hand side to have different array types for least_squares, least_squares_into and least_squares_in_place.

[codecov]

Codecov Report

Merging #272 (a23224f) into master (28c7860) will increase coverage by 0.06%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #272      +/-   ##
==========================================
+ Coverage   89.04%   89.10%   +0.06%     
==========================================
  Files          71       71              
  Lines        3586     3606      +20     
==========================================
+ Hits         3193     3213      +20     
  Misses        393      393              

Impacted Files	Coverage Δ
ndarray-linalg/src/least_squares.rs	98.88% <100.00%> (+0.14%)	⬆️

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[termoshtt]

This is relevant. Thanks!