Rename generic_mat***mul! to mul!

[dkarrasch]

Follow-up to JuliaLang/LinearAlgebra.jl#1671.

This will work only after JuliaLang/LinearAlgebra.jl#1676 is merged and LinearAlgebra.jl is bumped.

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.71%. Comparing base (2f05a07) to head (75cdfa2).

Files with missing lines	Patch %	Lines
src/linalg.jl	66.66%	1 Missing ⚠️
src/sparsevector.jl	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #746      +/-   ##
==========================================
- Coverage   84.40%   83.71%   -0.70%     
==========================================
  Files          13       13              
  Lines        9381     9380       -1     
==========================================
- Hits         7918     7852      -66     
- Misses       1463     1528      +65     

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[dkarrasch]

I can't get julia nightly to run on my machine. @araujoms Would you be able to check the call paths for the two methods that are seemingly uncovered?