fix: add BLAS.geru! manual doc

[hz-xiaxz]

closes #1401

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.85%. Comparing base (67c1103) to head (d9a8811).
Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1402   +/-   ##
=======================================
  Coverage   93.85%   93.85%           
=======================================
  Files          34       34           
  Lines       15827    15827           
=======================================
  Hits        14855    14855           
  Misses        972      972           

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[dkarrasch]

I think the comment is like a placeholder, like a to-do, that you have just done. ;-) You could remove that line.

[hz-xiaxz]

Yes but I found similar patterns here, https://github.com/JuliaLang/LinearAlgebra.jl/blob/67c1103e350bcce0ecc0c92a25ceac148e14b399/src/blas.jl#L53C4-L57C10, not sure why geru! is missing. I would fix it.